BENDIX EC-13 TRAILER ANTILOCK CONTROL User manual

1
SD-13-4783
Bendix®EC-13™Trailer AntiLock Controller Assembly
DESCRIPTION
GENERAL
Bendix trailer antilock systems utilizing the EC-13™
electroniccontrollerassemblyprovideAXLEbrakingcontrol
fortrailers. Bycontrolling“wheellock-up”duringaggressive
braking, the trailer retains a high degree of stability and
steerability while braking, and vehicle stopping distance
may be reduced.
In order to provide AXLE control antilock, the EC-13™
controller is used in combination with the following
components;
- Four, individual wheel speed sensors
- Two M-12R™remote mount modulator-relay valves
or a combination of one M-12™and one M-12R™
modulator
PHYSICAL
TheEC-13™controllerassemblyelectronics,whichregulate
the function of the antilock system, are contained in a die
castaluminum housing andare environmentally protected
bysiliconeencapsulation. Themetalhousing, coupled with
the design of the digital electronics, is intended to provide
ahigh degree ofprotectionfrom radio andelectromagnetic
interference.
A diagnostics display window with 9 light emitting diodes
(LEDs) and a magnetically actuated reset switch is
incorporated in the housing for troubleshooting and
diagnostic purposes.
A single electrical connector is currently used on the
EC-13™controller, for connection to the antilock system
components; a 30 pin, Packard Electric, 150 series “Metri-
pack.”
MOUNTING
TheEC-13™controllercan be remotebracketmountedto a
framemember or canbe mounted directlyon a modulator-
relayvalveassembly,suchastheBendix®M-12™modulator
(reference SD-13-4772). When the EC-13™controller is
mounted on a modulator assembly the resulting assembly
receives a different designation. For example when the
EC-13™antilock controller is mounted on the M-12™
modulator the resulting assembly (i.e.; EC-13™controller
plus M-12™modulator) is known as a MC-13™modulator
controller (see Figure 3). When the EC-13™controller is
bracket mounted to a frame member, and not mounted
on the modulator, an M-12R™modulator is used. The
M-12R™modulator is identical to the M-12™modulator but
has remote mounting capabilities (see Figure 6).
DIAGNOSTIC
WINDOW 30 PIN WIRE HARNESS
CONNECTOR
EC-13™Trailer AntiLock Controller
FIGURE 1 - EC-13™TRAILER ANTILOCK CONTROLLER
MOUNTING HOLES (4)

2
WS-20™
WHEELSPEED SENSOR
Reservoir
Reservoir
SPRING
BRAKE
SUPPLY (EMERGENCY) LINE
CONTROL(SERVICE) LINE
TO TRAILER ELECTRICAL
CONNECTOR SPRING BRAKE
M-12R™
MODULATOR
TRAILERANTILOCK
WIRING HARNESS
EC-13™CONTROLLER INFORMATION
INPUTS AND COMMAND OUTPUTS
GENERAL
The EC-13™controller receives information from several
components in the antilock system and, based on these
inputs, issues commands or delivers information. Some
portions of the EC-13™controller both receive and deliver
commands and information.
INPUTS
Wheel speed information is provided to the EC-13™
controllerviaawiringharnessfromindividualspeedsensors
located in the trailer wheels or axle housing. Working in
conjunction with an exciter or tone ring, the speed sensors
provide information to the EC-13™controller in the form of
anAC signal which varies in voltage and frequency as the
speed of the wheel increases or decreases. The EC-13™
controller is designed to receive wheel speed information,
fromvariouswheel speed sensor models,at therate of100
pulsesper wheel revolution. TheEC-13™controller is able
tosimultaneously receive, andindividually interpret,speed
signals from four wheel speed sensors (2 axles).
Vehicle power is supplied to the EC-13™controller
from the stop light switch. The electrical ground for the
EC-13™controller is from the 7 pin trailer connector and
trailer chassis.
OUTPUTS
Modulators, like the Bendix®M-12™and M-12R™
modulators, are the means by which the EC-13™antilock
controller is able to modify driver applied air pressure
to the service brakes. The EC-13™controller is able to
simultaneously and independently control two modulators
assemblies. The M-12™and M-12R™modulators are
combination valves consisting of a standard relay valve
and solenoid assembly. They replace the standard relay
valves used to speed up the application and release of the
trailer’s rear axle brakes. An external, three pin, wiring
harness connects the EC-13™controller to the M-12™or
M-12R™modulator solenoid assembly. For additional
information and service procedures see Bendix Service
Data Sheet SD-13-4772.
As stated previously, the EC-13™controller is designed to
control two modulators. It can be mounted directly on an
M-12™modulatorrelayvalveassemblyandcontrolaseparate
M-12R™modulator or the EC-13™controller can itself be
remote mounted to the trailer and control two M-12R™
modulators. When mounted directly on a modulator, the
two separate components (EC-13™controller and M-12™
modulator) become a single assembly called the MC-13™
modulator controller.
EC-13™
CONTROLLER
FIGURE 2 - TYPICAL EC-13™TRAILER ANTILOCK SYSTEM
30 PIN CONTROLLER
CONNECTOR
WS-20™
WHEELSPEED
SENSOR
SR-5™
SPRING BRAKE VALVE
M-12R™
MODULATOR

3
M-12™
Modulator
EC-13™
Controller
FIGURE 3 - TYPICAL MC-13™MODULATOR CONTROLLER
(EC-13™CONTROLLER & M-12™MODULATOR)
WS-20™Speed Sensor
90 Degree
Configuration
FIGURE 4 - WS-20™WHEEL SPEED SENSORS
Connectedto the EC-13™controllerviaa wire harness,the
modulatorisessentially a high capacity,on/offair valve that
incorporates a pair of electrical solenoids for control. The
solenoids provide the electric-air link between the antilock
controller electronics and the air brake system.
An optional indicator light can be connected to, and
controlled by, the EC-13™controller and serves as a
meansof advising thedriverof thecondition ofthe antilock
system.
The data link function enables the EC-13™controller to
“report” its operating condition to a specialized, external
computer in response to certain commands it receives.
The EC-13™controller data link configuration conforms to
S.A.E.standardJ1708andtheprotocol, or coded language
used, conforms to S.A.E. standard J1587. There are two
connections to the EC-13™controller devoted to the data
link. WhiletheEC-13™controlleris capable ofthis function,
and connections are provided, it is not always used. Use
of the data link is not essential for the EC-13™controller
to be functional.
OPERATION
OPERATIONAL PHILOSOPHY
The Bendix®EC-13™controller provides axle braking
control by using four speed sensors and two modulators.
By monitoring the rate of deceleration during braking, and
subsequently adjusting the brake application pressure to
eachaxle,theEC-13™controllerisabletoprovideimproved
braking while maintaining trailer stability.
The trailer’s rear axle brakes are controlled by the EC-13™
controller and two modulators (M-12™or M-12R™). Like
the standard service relay valve it replaces, the modulator
deliversbrakeapplicationpressuretotheservicechambers
on each axle. Two speed sensors on each axle “report”
changes in acceleration and deceleration to the EC-13™
controller. If required, the EC-13™controller adjusts the
applicationpressure to eitheraxle’sservice brakes,via the
modulators, based on the wheel behavior “reported” to it
by the speed sensors on each axle.
The EC-13™controller utilizes a “SELECT SMART” brake
control philosophy for the trailer brakes. This means
that the EC-13™controller will initially adjust application
pressure to the service chambers on either an axle based
on the speed information from the first wheel to approach
a locked condition. The initial pressure adjustment will
attempt to prevent either wheel on an axle from locking.
If a substantial braking difference is detected between two
wheels on an axle, the EC-13™controller will override the
first air pressure adjustment and allow one wheel to lock.
Both wheels including the locked wheel will continue to be
monitored for speed and braking difference changes that
wouldrequirepressure adjustments. Each ofthe twoaxles
is treated independent of the other.
NON-ANTILOCK BRAKE APPLICATION
Duringnormalbraking,thetractorbrakevalvesimultaneously
delivers air to the control port of the two trailer modulators.
Themodulators function the same as standard service relay
valves and apply air to the service brakes. The service
brakes are thus applied.
If the speed sensors do not detect an impending wheel
lock up, the EC-13™controller does not initiate any
correctiveaction and the trailercomesto a stopin anormal
fashion.
ANTILOCK CONTROLLED BRAKE
APPLICATION - SYSTEM FULLY OPERATIONAL
If a service brake application is made and the speed
sensors detect an impending wheel lockup on an axle,
the EC-13™controller will immediately begin modification
of the brake application using the antilock modulators at
the affected axle(s).
WS-20™Speed Sensor
Straight Configuration

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Solenoid valves contained in the modulator are energized
and de-energized by the EC-13™controller in order to
modify the brake application. When a solenoid coil is
energized its shuttle moves, and depending upon the
function of the specific solenoid, it either opens or closes,
thereby causing the exhaust or re-application of air
pressure to the relay valve portion of the modulator and to
thebrake actuators connected. Thesolenoidsin either the
M-12™or M-12R™modulator are controlled independently
by the EC-13™controller. By opening and closing the
solenoid valves in the appropriate modulator, the EC-13™
controller is actually simulating what the driver does when
he “pumps” the brakes.
It must be remembered however that unlike the driver, the
EC-13™controller is able to “pump” brakes on either the
front or rear axle(s), or both, independently and with far
greater speed and accuracy.
ANTILOCK SYSTEM OPERATION -
COMPONENT PROBLEM
The Bendix®EC-13™controller handles equipment
problems using a conservative fail-safe philosophy. Any
singleelectricalprobleminacomponentdevotedtoantilock
braking,results in simultaneousillumination of theantilock
condition lamp and a troubleshooting LED on the EC-13™
controller. Depending upon the type of problem and its
position of occurrence the EC-13™controller can continue
antilockfunctionat a lowerperformancelevel, disable all of
the antilock on the trailer or only a portion. When antilock
is disabled, the brakes on the affected axle(s) revert to
standard air braking.
System Parts Still Operating ( Yes / No )
Problem ABS Lead ABS Rear
Location Axle Axle
LeadAxle Rt. Sensor Yes Yes
LeadAxle Lft. Sensor Yes Yes
RearAxle Rt. Sensor Yes Yes
RearAxle Lft. Sensor Yes Yes
LeadAxle Modulator No Yes
RearAxle Modulator Yes No
Controller No No
Voltage * No No
* If electrical power is below or above the 7 to 18 volt operating
range the ABS will stop operating. If voltage returns to the 8-17
volt range the ABS is restored.
A problem in a single speed sensor will not result in
disablingofthe antilock system. Ifa speedsensor problem
is detected by the EC-13™controller, the remaining speed
sensor on the axle will be used to continue antilock
operation on the axle but at a slightly degraded level of
performance.
Withthefailedcomponentapproachdescribed, the antilock
system will attempt to provide the trailer with the best
possible braking and stability even after a problem has
occurred. It should be remembered that the driver will be
advisedof any degraded antilock operation via thecondition
lamp and that standard air braking will still be available on
those brakes where the antilock has been disabled.
ANTILOCK WIRING
GENERAL NOTES
The wires that carry information and power into and out of
theEC-13™controlleraregroupedandterminateat a 30 pin
Packardconnector which plugsinto the EC-13™controller.
The wiring harnesses and connectors are weather proof
and the wires that enter the connector are sealed to the
connector. The wire gauge used in the wire harnesses is
specific to the task performed.
When diagnosing wiring in the antilock system the following
general rules apply and should be followed where applicable:
1. Itis generally advisable to replacea wire harnessrather
than repair individual wires in the harness. If a splice
repair must be made, it is important that the splice be
properlysoldered with arosin flux (notacid based) and
the splice made water proof.
2. Do not pierce wire insulation when checking for
continuity. Check for power, ground or continuity by
disconnecting the connector and testing the individual
pins or sockets in the connector(s). Do not overstress
sockets.
3. Always check the vehicle hand book for wire and
connector identification. Individual wire identification
will differ depending upon the type of connectors in
use, the trailer manufacturer, and the system features
in use.
4. While the serial link connections (2 total) are present
on all EC-13™controllers they are not always used. In
addition several connector openings are not used.
PREVENTATIVE MAINTENANCE
Every 3 months; 25,000 miles; or 900 operating hours:
1. Check all wiring and connectors to ensure they are
secure and free from visible damage.
2. Although the EC-13™controller incorporates a self
checkdiagnostics,theLEDdisplayshouldbe inspected
to ensure that they are functional. With the tractor
ignition on and a brake application held applied, hold
a magnet (800 gauss; capable of picking up 3 ounces)
on the diagnostic window reset switch and note all of
the LEDs illuminate. If one or more of the LEDs DO
NOT ILLUMINATE and the antilock condition lamp on
the trailer indicates the system is functioning properly,
the non-illuminated LED(s) should be noted for future
reference. Although the diagnostic capabilities will
be limited, the system will continue to function as
designed.

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12
Wheel Speed
Connector
(to Sensor)
Modulator
Connector
(to Modulator)
Trailer Service Air Line
Trailer Wiring
Harness Connector
3
3
2
1
WS-20™Wheel Speed Sensor
TAIL
LIGHTS
(BRN)
BRAKE
(RED)
LEFT TURN
LIGHTS
(YLW)
POWER
(BLUE)
MAKER
LIGHTS
(BLK)
GROUND
(WHT)
Trailer Electrical
Connector
Note:
Connector terminals not listed in the chart
are currently not in use.
Typical Trailer Connector
Terminal Allocation
3
3
Wire Harness Connector
(to Trailer Electrical
Connector)
Trailer Electrical
Connector
Spring Brake
Trailer AntiLock
Status Light
M-12R™
Modulator
1
M-12R™
Modulator
FIGURE 5 - TYPICAL MC-13™MODULATOR CONTROLLER TRAILER WIRING SCHEMATIC
Trailer Wiring Harness
Connector
(Connects to EC-13™Controller)
RIGHT
TURN
LIGHTS
(GRN)
Terminal Connection 1K & 2K Battery Power (+) Stop Light Switch 1A& 2A Trailer Ground 3F Trailer Status Lamp 1G Front Modulator Common 2G Front Modulator Hold 2F Front Modulator Exhaust 1D Rear Modulator Common 1C Rear Modulator Hold 1B Rear Modulator Exhaust 3J Left Front Wheel Speed Signal 3H Left Front Wheel Speed Signal 2H Right Front Wheel Speed Signal 3K Right Front Wheel Speed Signal 3E Left Rear Wheel Speed Signal 2C Left Rear Wheel Speed Signal 3D Right Rear Wheel Speed Signal 3C Right Rear Wheel Speed Signal 3A SerialA 3B Serial B

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EC-13™
Controller
M-12R™
Modulator
(Remote
Mount)
FIGURE 6 - EC-13™CONTROLLER AND M-12R™
MODULATOR ASSEMBLY
3. Road test the trailer by making an antilock stop from a
vehicle speed of 20 miles per hour. When an antilock
stop is made, the modulator solenoids pulsate and an
audible burst of air can be heard. The wheels should
not enter a prolonged “lock” condition.
WARNING! PLEASE READ AND FOLLOW
THESEINSTRUCTIONSTOAVOID PERSONAL
INJURY OR DEATH:
When working on or around a vehicle, the following
general precautions should be observed at all times.
1. Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.
2. Stop the engine and remove ignition key when
working under or around the vehicle. When
working in the engine compartment, the engine
should be shut off and the ignition key should be
removed. Where circumstances require that the
engine bein operation, EXTREMECAUTION should
be used to prevent personal injury resulting from
contact with moving, rotating, leaking, heated or
electrically charged components.
3. Do not attempt to install, remove, disassemble
or assemble a component until you have read
and thoroughly understand the recommended
procedures. Use only theproper tools and observe
all precautions pertaining to use of those tools.
4. If the work is being performed on the vehicle’s
air brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure
from all reservoirs before beginning ANY work
on the vehicle. If the vehicle is equipped with an
AD-IS®air dryersystem or adryer reservoirmodule,
be sure to drain the purge reservoir.
5. Followingthevehiclemanufacturer’srecommended
procedures, deactivate the electrical system in a
manner that safely removes all electrical power
from the vehicle.
6. Never exceed manufacturer’s recommended
pressures.
7. Never connect or disconnect a hose or line
containing pressure; it may whip. Never remove
a component or plug unless you are certain all
system pressure has been depleted.
8. Use only genuine Bendix®replacement parts,
components and kits. Replacement hardware,
tubing, hose, fittings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifically for such applications and
systems.
9. Components with stripped threads or damaged
parts should be replaced rather than repaired. Do
not attempt repairs requiring machining or welding
unless specifically stated and approved by the
vehicle and component manufacturer.
10. Prior to returning the vehicle to service, make
certain all components and systems are restored
to their proper operating condition.
11. For vehicles with Antilock Traction Control (ATC),
the ATC function must be disabled (ATC indicator
lamp should beON) prior to performingany vehicle
maintenance where one or more wheels on a drive
axle are lifted off the ground and moving.
REMOVING EC-13™CONTROLLER ASSY
Locate the EC-13™controller on the trailer and determine
ifit is mountedon a modulator(e.g. M-12™modulator) oris
remotemountedto a trailerframe memberusingabracket.
Use the appropriate removal procedure below.
Removing the EC-13™Controller and M-12™Modulator:
1. Identify and remove all air lines connected to the
M-12™modulator.
2. Disconnect the electrical connector (on the vehicle
wiring harness) from the EC-13™controller.
3. Note and mark the mounting position of the MC-13™
modulator- controller assemblyonthe trailer. Loosen,
remove and save the nuts on the mounting hardware
that attaches the MC-13™modulator controller bracket
tothe trailer. RemovetheMC-13™modulator-controller
assembly from the trailer.
4. Remove as much contamination as possible from
the exterior of the assembly making sure to keep the
contamination away from the open ports.
5. Note and mark the position of the EC-13™controller
relativetotheM-12™modulator. Removeand retain the
four hex cap screws that secure the EC-13™controller
tothe M-12™modulator. Carefullyseparate the EC-13™
controller from the M-12™modulator enough to expose
the wire harness that connects both units electrically.
Disconnect the wire harness by separating the four pin
connectorattheEC-13™controller. Peelthegasketfrom
the EC-13™controller or M-12™modulator and retain
for reuse. Note: Use a new gasket if damaged during
removal or if a new gasket is immediately available.

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Removing a Bracket Mounted Remote EC-13™Controller:
1. Disconnect the electrical connector (on the vehicle
wiring harness) from the EC-13™controller.
2. Note and mark the mounting position of the EC-13™
controllerassemblyon the trailer. Loosen,removeand
save the mounting hardware that attaches the EC-13™
controller bracket to the trailer. Remove the EC-13™
controller and bracket assembly from the trailer.
INSTALLING EC-13™CONTROLLER ASSY
Installing the EC-13™Controller and M-12™Modulator:
1. After noting the positioning marks made prior to
disassembly, reconnect the M-12™modulator wire
harness to the EC-13™controller, position the gasket
on the EC-13™controller then secure the EC-13™
controller to the M-12™modulator using the four cap
screws. Torque the cap screws to 50-80 lbs. in.
2. Mount the assembled MC-13™modulator controller on
the trailer and orient it in the position marked prior to
removal.
3. Reconnect all air lines.
4. Reconnect the electrical connector (on the vehicle
wiring harness) to the EC-13™controller.
5. TesttheMC-13™modulator controller foroperation and
air leakage prior to placing the trailer in service.
6. Perform the “Initial Start-up Procedure” in the
TROUBLESHOOTING section to assure proper
antilock system operation.
INSTALLING A BRACKET MOUNTED REMOTE
EC-13™CONTROLLER
1. Using the mounting hardware retained in step 2 of the
removal mount the EC-13™controller in the position
noted during removal.
2. Reconnect the electrical connector (on the vehicle
wiring harness) to the EC-13™controller.
DIAGNOSING AND LOCATING A SYSTEM
PROBLEM
GENERAL
The EC-13™controller contains self test and diagnostic
circuitry that continuously checks for proper operation of
the entire antilock system including wiring continuity. An
optionalconditionlamp,controlledbytheEC-13™controller,
advises the driver of the condition of the entire antilock
system.
The condition of specific antilock components is provided
to the mechanic by a series of labeled, light emitting
diodes (LEDs) displayed through a “window” in the
EC-13™controller housing. No special tools or equipment
are needed to read or interpret the EC-13™controller
diagnosticswindow. Itshould be noted thatthe diagnostics
display is separate from the antilock condition lamp on
the trailer. With this separation, the driver is aware of any
problems that occur but is not confused by the diagnostic
information.
A special feature of the EC-13™controller diagnostic
system is its problem indication latching. Intermittent
problems,particularly in the wheelspeedsensing area can
be difficult to diagnose. When the controller senses an
erroneous condition, whether in the controller electronics,
the modulator or speed sensing areas, it stores the
condition in non-volatile memory, disables the antilock
function if necessary, illuminates the condition lamp and
the appropriate diagnostic LEDs on the EC-13™controller.
The condition is truly stored and is not cleared by loss of
power to the EC-13™controller. The LEDs will re-light
when power is restored and remain illuminated until the
problemiscorrected. After the actualproblem iscorrected,
maintenance personnel can clear or reset the EC-13™
controller diagnostics by passing a small magnet over the
RESET point in the diagnostics window.
DIAGNOSTIC LEDS
There are nine LEDs plus a magnetically actuated reset
switch in the EC-13™controller diagnostic window. The
first five LEDs locate a problem to a specific area of the
trailer while the last four indicate the problem component
or its wiring. The LEDs are computer controlled and are
either ON or OFF depending upon their monitor function.
(Note: Right and left, front and rear are determined from
the driver’s seat. Left front is therefore the corner closest
to the driver.)
LED o FRONT Red LED
LED o MID Red LED (SEE NOTE BELOW)
LED o REAR Red LED
LED o RIGHT Red LED
LED o LEFT Red LED
LED o MOD Red LED
LED o SENS Red LED
LED o ECU Red LED
LED o VOLT Green LED
¦ ¦ ¦ RESET No LED
EC-13™
Controller
EC-13™
Controller
Diagnostic
Window
LED Indicators
FIGURE 7 - EC-13™CONTROLLER DIAGNOSTIC WINDOW

8
NOTE: The MID LED shown in the chart on the previous
page is not used in the diagnostic process for
the EC-13™controller however, it will light when
a magnet is placed on the RESET switch in the
diagnostic window.
“FRONT” LED
ThisredLEDilluminatesandlatchesONin order to indicate
the location of a problem component or its wiring. It will
lightin conjunction with eithertheRIGHTorLEFTLEDand
the SENS LED when indicating a speed sensor problem.
TheFRONTLED willalso lightin conjunctionwith theMOD
LEDtoindicatethat the frontmodulator (M-12™orM-12R™)
or its wiring has malfunctioned.
“MID” LED
This red LED is not used in troubleshooting the EC-13™
controller and should light only when a magnet is held on
the RESET switch.
“REAR” LED
ThisredLEDilluminatesandlatchesONin order to indicate
the location of a problem component or its wiring. It will
lightin conjunction with eithertheRIGHTorLEFTLEDand
the SENS LED when indicating a speed sensor problem.
The REAR LED will also light in conjunction with the MOD
LEDtoindicate that the rearmodulator (M-12™)or its wiring
has malfunctioned.
“RIGHT” LED
ThisredLEDilluminatesandlatchesONin order to indicate
the location of a problem component or its wiring. It will
light in conjunction with either the FRONT or REAR LED
and SENS LED. This LED SHOULD NOT LIGHT when a
MOD LED is on.
“LEFT” LED
ThisredLEDilluminatesandlatchesONin order to indicate
the location of a problem component or its wiring. It will
light in conjunction with either the FRONT or REAR LED
and SENS LED. This LED SHOULD NOT LIGHT when a
MOD LED is on.
“MOD” LED
This red LED illuminates and latches ON to indicate a
permanent or intermittent open or short circuit in the
solenoids of one of the two modulators or the wiring
connecting them to the system. The MOD LED will
illuminate in conjunction with either the FRONT or REAR
LED.
“SENS” LED
This red LED illuminates and latches ON to indicate
permanent or intermittent problem. The failures indicated
are; open or shorted wheel speed sensor, open or shorted
wheelspeedsensor wiring, wheel speedsignal notpresent
ordoes notconform to designcriteria. The SENSLED will
illuminate in conjunction with either the FRONT or REAR
and either the RIGHT or LEFT LED.
“ECU” LED
ThisredLED,whenilluminated,indicates that the controller
itself has failed. It is latched ON for all EC-13™controller
failures except low voltage. For voltages less than 6 vdc,
theLED illuminates toindicatethe controller isinoperative,
however when the voltage again exceeds 6 vdc the LED
will go OUT by itself.
“VOLT” LED
This green LED illuminates and remains ON during trailer
operation to indicate that vehicle power is reaching the
controller(LEDONonly when a brakeapplication is made).
If vehicle power is out of range for proper operation (below
7 vdc or above 18 vdc) this LED will flash until power is
brought into range. This LED may also flash indicating
that a “marginal” low voltage condition existed at the time
of an antilock event.
“RESET”
Beneath the RESET area of the window display is a
magnetically sensitive switch that is used to reset the
diagnostic system. The device will respond to a magnet
whichhasstrength sufficient to lift athree (3)ounce weight.
Holding a magnet against the RESET will cause all LEDs
to light during the time the magnet is against it.
TROUBLESHOOTING
GENERAL
While the EC-13™controller diagnostic display locates
a specific problem area, it is still necessary to confirm
whether the problem resides in the component itself or
the wiring. Basically the troubleshooting procedure that
follows is devoted to narrowing the problem to either the
wiringor a specificantilock component. Itshouldbe noted
thatALLTROUBLESHOOTING BEGINS BYOBSERVING
THEANTILOCKSTATUSLAMPONTHETRAILERWHILE
PERFORMING THE “INITIAL START-UP PROCEDURE”
and following the directions contained in the procedure.

9
IMPORTANT - TROUBLESHOOTING TIPS
1. Record all findings and the action taken during the
troubleshooting process. The record sheet should be
filedinthetrailermaintenancefolderforfuturereference
and comparison.
2. No voltage or resistance tests are performed into
the EC-13™controller. All voltage and resistance
tests are performed by beginning at the wire harness
half of the connector and moving AWAY from the
EC-13™controllertowardanantilocksystemcomponent
(modulator, wheel speed sensor, etc.)

10
START HERE
STATUS LAMP DOES NOT BLINK, COMES
ON AND REMAINS ILLUMINATED
YES
NO
STATUS LAMP COMES ON, BLINKS AND
GOES OUT.
THE SYSTEM IS FUNCTIONING NORMALLY.
MAKE NOTES OF THE PARTS REPLACED OR
REPAIRED AND STEPS TAKEN .
AMBER STATUS LAMP
BLINKS ONCE, THEN GOES OUT
SYSTEM - OK
WITH TRAILER CONNECTED TO
TRACTOR, TURN IGNITION ON,
APPLY TRAILER SERVICE BRAKES
AND OBSERVE STATUS LAMP
MOUNTED ON TRAILER.
NO
DID STATUS LAMP ILLUMINATE?
GO TO SECTION I “STATUS
LAMP TESTING”
ARE STOP LAMPS
ILLUMINATED
YES
TEST FOR POWER TO THE
TRAILER AT 7 PIN CONNECTOR
NO
YES
GO TO SECTION II
“INSPECTION FOR
ILLUMINATED LEDS ”.
Troubleshooting
INITIAL START-UP PROCEDURE
TYPICALLOCATIONS
FORAMBER
STATUS LAMP

11
Troubleshooting
SECTION I
TRAILER STATUS LAMP TESTING
REPEAT THE “INITIAL
START-UP PROCEDURE”.
START HERE
USING A JUMPER WIRE CONNECT PIN 3F TO 1AAND/
OR 2A. WITH THE CONNECTION IN PLACE NOTE THE
CONDITION OF TRAILER STATUS LAMP.
TRAILER STATUS LAMP ON?
NO
YES REPLACE EC-13™CON-
TROLLER AND RETEST.
CHECK THE FOLLOWING IN THE ORDER PRESENTED AND
AFTER REPLACING OR TESTING EACH COMPONENT,
TEST THE STATUS LAMP OPERATION:
1. CHANGE TRAILER STATUS LAMP BULB
2. CHECK TRAILER STATUS LAMP WIRING-GROUND
3. CHECK CONTINUITY OF WARNING WIRE BETWEEN PIN
3F ON THE 30 PIN CONNECTOR AND THE TRAILER STATUS
LAMP SOCKET
EC-13™CONTROLLER
WIRE HARNESS CONNECTOR
WITH TRACTOR IGNITION OFF,
DISCONNECT 30 PIN WIRE HARNESS
CONNECTOR FROM EC-13™CONTROLLER
THEN TURN TRACTOR IGNITION ON AND
MAKE AND HOLD A BRAKE APPLICATION.
TRAILER STATUS
LAMP 3F
GROUND 1A & 2A

12
Troubleshooting
SECTION II
INSPECTION FOR ILLUMINATED LED’s
YES YES
GO TO SECTION IV
“TESTING FOR POWER
TO THE
EC-13™CONTROLLER”.
NO
NO
START HERE
IS GREEN, VOLT, LED ILLUMINATED?
REPLACE THE EC-13™
CONTROLLER
ARE ANY RED
LED’s
ILLUMINATED?
IS GREEN LED FLASHING
NO
ARE ANY RED LED’s ILLUMINATED?
YES
NO
YES
GO TO SECTION IV
“TESTING FOR POWER
TO THE
EC-13™CONTROLLER”.
NOTE AND RECORD
THE CONDITION OF
ALL RED LEDS
GO TO SECTION III “INSPECTION
FOR ILLUMINATED LEDS”.
ON? FLASHING?
RED LEDs
ANY ILLUMINATED?
CHECKING
“VOLT” LED
WITH TRACTOR IGNITION ON AND BRAKES HELD
APPLIED, INSPECT EC-13™CONTROLLER FOR
PRESENCE OF ILLUMINATED LEDS AND RECORD.
GO TO SECTION I “TRAILER STATUS
LAMP TESTING”.

13
Troubleshooting
SECTION III
INSPECTION FOR ILLUMINATED LEDS
NO
IS RED “SENS” LED
ILLUMINATED?
NOTE THE THREE
ILLUMINATED LEDS AND
GO TO SECTION VI
“TESTING THE WHEEL
SPEED SENSOR”
REPLACE THE EC-13™
CONTROLLER AND
REPEAT THE “INITIAL
START-UP PROCEDURE”
YES
IS THE RED “FRONT”
OR “REAR” LED
ILLUMINATED?
SEE NOTE 1 BELOW
NO
YES
NO
NO
YES
YES
IS RED “MOD” LED
ILLUMINATED?
YES YES
NO
IS THIS LED ILLUMINATED? GO TO SECTION IV “TESTING
FOR POWER TO THE EC-13™
CONTROLLER”.
YES
NOTE RED “ECU” LED
IN EC-13™CONTROLLER
DIAGNOSTICS WINDOW.
START HERE
NO
NO
IS THE RED “RIGHT”
OR “LEFT” LED
ILLUMINATED?
SEE NOTE 1 BELOW
IS THE RED “FRONT”
OR “REAR” LED
ILLUMINATED?
SEE NOTE 1 BELOW
ON
SEE NOTE 1
SEE NOTE 1
SEE NOTE 1
SEE NOTE 2
ON
IS THE RED “RIGHT”
OR “LEFT” LED
ILLUMINATED?
SEE NOTE 2 BELOW
TESTING “MOD”
LED
TESTING “SENS”
LED
INSPECTING “ECU”
LED
IF ANY OTHER RED
LEDs ARE ILLUMINATED,
REPLACE THE EC-13™
CONTROLLER AND
REPEAT THE “INITIAL
START-UP PROCEDURE”
GO TO SECTION V
“TESTING THE
MODULATOR”
NOTES:
1. IF BOTH OF THESE LEDs ARE ILLUMINATED,
REPLACE THE EC-13™CONTROLLER
2. IF EITHER OF THESE LEDs ARE ILLUMINATED,
REPLACE THE EC-13™CONTROLLER
ON?

14
Troubleshooting
SECTION IV
TESTING FOR POWER TO THE EC-13™CONTROLLER
TURN IGNITION OFF, DISCONNECT WIRE
HARNESS CONNECTOR FROM EC-13™
CONTROLLER
START HERE
VOLTAGE SAMEAS
BATTERY VOLTAGE? MUST BE
BETWEEN 8 AND 17 VOLTS.
NO
WIRE HARNESS CONNECTOR
RECONNECT CONNECTOR TO EC-13™
CONTROLLER. CHECK THE VEHICLE
WIRING FOR CONTINUITY. REFER TO THE
VEHICLE SERVICE MANUALAND CHECK
THE BATTERY VOLTAGE. REPAIR OR
REPLACEAS NECESSARYAND REPEAT
THE “INITIAL START-UP PROCEDURE”
YES
REPLACE EC-13™
CONTROLLER
REPEAT THE
“INITIAL START-UP
PROCEDURE”.
CHECKING “VOLT”
LED
ON OR FLASHING?
YES
NO
RESETTING
EC-13™
CONTROLLER
MAGNET HERE
PERFORM A MAGNETIC RESET
BY PASSING A MAGNET OVER THE
“RESET” IN EC-13™CONTROLLER
DIAGNOSTIC WINDOW THEN
REMOVE MAGNET
TURN IGNITION OFF, RECONNECT
WIRE HARNESS TO EC-13™
CONTROLLER, TURN IGNITION ON
1K, 2K
POWER
1A, 2A
GROUND
IS THE GREEN, “VOLT” LED
STILL FLASHING OR RED
“ECU” LED STILL ON?
ON ?
TURN IGNITION ON, MAKE & HOLD A BRAKE
APPLICATION AND, MEASURE VOLTAGE
BETWEEN POWER AND GROUND PINS ON
WIRE HARNESS CONNECTOR
1ATO 1K
1ATO 2K
2ATO 1K
2ATO 2K

15
SAME RED LED’s
ILLUMINATED?
NO
YES
YES
ARE ANY RED LED’s
ILLUMINATED?
INSPECT CONNECTOR AND RECONNECT
TO EC-13™CONTROLLER. TURN IGNITION
ON AND PASS MAGNET OVER “RESET” ON
EC-13™CONTROLLER. REMOVE MAGNET
AND NOTE REACTION OF RED LEDS.
ARE RESISTANCE
VALUES CORRECT?
YES
GO TO SECTION V BAND
CONTINUE TESTING
NO
REPEAT “INITIAL START-UP
PROCEDURE”. IF TESTING HAS
RETURNED TO THIS STEP TWICE -
REPLACE THE EC-13™CONTROLLER.
REPLACE EC-13™
CONTROLLER
NO
GO TO SECTION III
“INSPECTION FOR
ILLUMINATED LEDS”
AND RETEST.
IF FAILURE PERSISTS,
REPLACE THE EC-13™
CONTROLLER.
PROBE CONNECTOR WITH VOLT/OHM METER AND NOTE THAT
PROPER RESISTANCE VALUESARE OBTAINED FOR
MODULATOR BEING TESTED. RESISTANCE VALUES HERE FOR A
BENDIX®M-12™MODULATOR.
FRONT MODULATOR
HOLD TO SOURCE (2G TO 1G): READ 9 TO 12 OHMS
EXHAUST TO SOURCE (2F TO 1G): READ 9 TO 12 OHMS
EXHAUST TO HOLD (2F TO 2G): READ 18 TO 24 OHMS
SOURCE TO POWER (1G TO 1K, 2K): NO CONTINUITY
SOURCE TO GROUND (1G TO 1A, 2A): NO CONTINUITY
REAR MODULATOR
HOLD TO SOURCE (1C TO 1D): READ 9 TO 12 OHMS
EXHAUST TO SOURCE (1B TO 1D): READ 9 TO 12 OHMS
EXHAUST TO HOLD (1B TO 1C): READ 18 TO 24 OHMS
SOURCE TO POWER (1D TO 1K, 2K): NO CONTINUITY
SOURCE TO GROUND (1D TO 1A, 2A): NO CONTINUITY
TURN IGNITION OFF. DISCONNECT
30 PIN WIRE HARNESS CONNECTOR
FROM EC-13™CONTROLLER.
START HERE
WIRE HARNESS CONNECTOR
2F
EXHAUST 2G
HOLD
1A, 2A
GROUND 1K, 2K
POWER
1G
SOURCE
1C
HOLD
1B
EXHAUST 1D
SOURCE
MAGNET HERE
RESETTING
EC-13™
CONTROLLER
Troubleshooting
SECTION V PART A
TESTING THE MODULATOR

16
Troubleshooting
SECTION V PART B
TESTING THE MODULATOR
MAGNET HERE
RESETTING
EC-13™
CONTROLLER
RESISTANCE IN RANGE? REPLACE M-12™
MODULATOR ASSEMBLY
GO TO SECTION III - “INSPECTION
FOR ILLUMINATED LEDs”
ARE ANY RED LEDs
ILLUMINATED? REPEAT THE “INITIAL
START-UP PROCEDURE”
ARE THE SAME RED
LEDs ILLUMINATED? REPLACE THE
EC-13™CONTROLLER.
NO
YES
YES
NO
NO
YES
RECONNECT EC-13™CONTROLLER TO
M-12™MODULATOR. TURN IGNITION
ON AND PASS MAGNET OVER
“RESET” ON EC-14™CONTROLLER
AND REMOVE. NOTE REACTION OF
RED LEDS.
START HERE
TURN THE IGNITION OFF. DISCONNECT THE
MODULATOR (M-12™OR M-12R™) CONNECTOR
FROM THE VEHICLE WIRE HARNESS TO EXPOSE
THE THREE PIN CONNECTOR LEADING TO THE
M-12™MODULATOR AND TEST RESISTANCE
BETWEEN THE PINS ON THE
MODULATOR CONNECTOR.
RED TO BLACK 9 TO 12 OHMS
RED TO WHITE 9 TO 12 OHMS
M-12™MODULATOR
WIRE HARNESS
CONNECTOR
BLACK WHITE
RED

17
Troubleshooting
SECTION VI PART A
TESTING THE WHEEL SPEED SENSOR
START HERE
TURN IGNITION OFF AND CHECK FOLLOWING:
A. REMOVE CONNECTOR(S) FROM EC-13™CONTROLLERAND MEASURE
RESISTANCE BETWEEN APPROPRIATE SPEED SENSOR SIGNAL (+)
AND SIGNAL RETURN (-). RESISTANCE FOR BENDIX®WS-20™SPEED
SENSOR SHOULD BE BETWEEN 1500-2500 OHMS. REFER TO VEHICLE
MAINTENANCE MANUAL IF OTHER THAN THE WS-20™SENSOR IS IN
USE. IF RESISTANCE NOT CORRECT, DISCONNECT CONNECTOR AT
SPEED SENSOR. INSPECT CONNECTOR, THEN CHECK RESISTANCE
BETWEEN PINS ON SENSOR. IF RESISTANCE IS NOT CORRECT
(BETWEEN 1500-2500 OHMS FOR THE BENDIX®WS-20™SENSOR),
REPLACE SENSOR, OTHERWISE PROCEED TO STEP B.
B. CHECK “GAP” BETWEEN SPEED SENSOR AND EXCITER OR TONE
RING. (GAP FOR BENDIX®WS-20™SPEED SENDER IS BETWEEN 0 - .015
INCHES) IF SENSOR GAP MUST BE ADJUSTED, CHECK FOR LOOSE OR
WORN WHEEL BEARINGS BEFORE RE-GAPPING SENSOR. REFER TO
VEHICLE MAINTENANCE MANUAL FOR WORN BEARINGS.
C. IF SENSOR GAP IS CORRECT CHECK WHEEL BEARING FOR FREE PLAY
TO VERIFY IT COMPLIES TO MANUFACTURER’S RECOMMENDATIONS.
D. MAKE CERTAIN EXCITER OR TONE RING IS IN PLACEAND INSPECT
CONDITION. CHECK FOR MISSING OR DAMAGED TEETH AND THAT IT
RUNS TRUE AND PERPENDICULAR TO SENSOR FACE.
E. CHECK WIRING HARNESS AND CONNECTORS THAT RUN TO SENSOR.
F. CHECK FOR DRAGGING BRAKES (OVER ADJUSTED, TRAPPED AIR
IN ACTUATOR, OUT OF ROUND DRUMS, FAULTY RETURN SPRINGS,
PARKING BRAKE SYSTEM FAULTS, ETC.) AND CORRECTAND RETEST.
TESTING SPEED SENSOR RESISTANCE
REPEAT THE “INITIAL START-UP
PROCEDURE
ARE ANY RED LEDs
ILLUMINATED?
GO TO SECTION III - “INSPECTION
FOR ILLUMINATED LEDs”
NO
YES
GO TO SECTION VI PART B
AND BEGIN TESTING
ANY RED LED’s ON?
NO
RESETTING
EC-13™
CONTROLLER
MAGNET HERE
PASS MAGNET OVER “RESET” ON
EC-13™CONTROLLER. REMOVE
MAGNETAND OBSERVE THE LEDs.
RECONNECT EC-13™CONTROLLER,
TURN IGNITION ON. PASS MAGNET OVER
“RESET” ON EC-13™CONTROLLER.
REMOVE MAGNETAND OBSERVE LEDs
YES
3H
LFT. FRONT
3D
RT. REAR
3C
RT. REAR
3E
LFT. REAR
2C
LFT. REAR
EC-13™CONTROLLER WIRE
HARNESS CONNECTOR
2H
RT. FRONT
3J
LFT. FRONT
3K
RT. FRONT
RESETTING
EC-13™
CONTROLLER
MAGNET HERE

18
Troubleshooting
SECTION VI PART B
TESTING THE WHEEL SPEED SENSOR
REPEAT THE “INITIAL
START-UP PROCEDURE”.
REPLACE THE EC-13™
CONTROLLER
YES
ARE ANY LED’s ILLUMINATED?
YES
ARE SAME RED LEDS ILLUMINATED?
YES
CORRECT RESISTANCE?
NO
DISCONNECT CONNECTORAT SPEED SENSOR. INSPECT
THE CONNECTOR,THEN CHECK THE RESISTANCE
BETWEEN TWO PINS ON SENSOR. RESISTANCE BETWEEN
1500-2500 OHMS FOR THE BENDIX®WS-20™SENSOR
YES
REPLACE THE SENSOR
NO
NO
GO TO SECTION III “INSPECTION
FOR ILLUMINATED LED’s”
NO
RESETTING
EC-13™
CONTROLLER
MAGNET HERE
START HERE FROM
SECTION VI PART A GO TO SECTION III “INSPEC-
TION FOR ILLUMINATED LED’s”
SAME LED’s ILLUMINATED? NO
YES
RECONNECT CONNECTORAT
SPEED SENSOR AND EC-13™
CONTROLLER. PASS MAGNET
OVER “RESET” ON EC-13™
CONTROLLER. REMOVE MAGNET
AND OBSERVE LEDs
IGNITION OFF. REMOVE 30 PIN CONNECTOR FROM EC-13™
CONTROLLER. MEASURE RESISTANCE BETWEEN THE
APPROPRIATE SPEED SIGNAL PINS ON THE CONNECTOR.
RESISTANCE FOR BENDIX®WS-20™SENSOR IS BETWEEN
1500-2500 OHMS. REFER TO VEHICLE MANUAL FOR THE RE-
SISTANCE VALUES IF OTHER THAN WS-20™SENSOR IS IN USE.
REPAIR OR REPLACE SPEED
SENSOR WIRING HARNESS
AND REPEAT THE “INITIAL
START-UP PROCEDURE”.
3H
LFT. FRONT
3D
RT. REAR
3C
RT. REAR
3E
LFT. REAR
2C
LFT. REAR
EC-13™CONTROLLER WIRE
HARNESS CONNECTOR
TESTING SPEED SENSOR
RESISTANCE
3K
RT. FRONT
3J
LFT. FRONT
2H
RT. FRONT

19

20 BW1823 © 2007 Bendix Commercial Vehicle Systems LLC. All rights reserved. 8/07 Printed in U.S.A.