Dexter Laundry DX Series User manual

SERVICE MANUAL
DX SERIES ELECTRIC/HYDRAULIC ACTUATOR
www.dexteraxle.com

2021.02 | 2 DX SERIES SERVICE MANUAL
ELECTRIC/HYDRAULIC ACTUATORS
Introduction ...............................................................2
Installation Instructions...............................................2
Electrical Wire Colors and Function...............................3
Electrical Installation Requirements.............................4
Electrical Schematic...........................................................4
Test Electrical Operation ..............................................5
Bleeding and Brake Adjustment....................................5
Sleep Mode .................................................................6
Electric Controller Unit Testing/Adjusting.....................6
Troubleshooting Guide .................................................7
Aftermarket Kits .................................................................7
Before proceeding, make sure that the unit is appropriate for your
particular brakes. The E/H 1000 produces 1000 psi, typically used
for duo-servo hydraulic drum brakes, while the E/H 1600 produces
1600 psi for most hydraulic disc brakes. Please refer to your brake
manufacturer for proper operating pressures.
The Dexter DX Series brake actuator is compatible with many electric
brake controllers, but the best performance will be achieved using an
inertial type controller such as the Dexter Predator DX2®. The electronic
timer type of controller is not recommended because these units use a
xed control that does not sense varying brake requirements.
Please reference 059-A38-00 DX Series Compatibility Guide,
available at www.dexteraxle.com for more information on brake
controller compatibility.
CAUTION
It is the responsibility of the end user to ensure that their electric
brake controller is compatible with the Dexter DX Series brake
actuator. Dexter attempts to provide compatibility with most
controllers available, but is unable to anticipate design changes
that might be introduced by the various controller manufacturers.
Installation Instructions
The following materials are required to properly install the Dexter DX
Series brake actuator. If your trailer is not already equipped with brake
lines, you will need enough 3/16” diameter automotive brake line to
connect the trailer brakes to the unit. Where possible, steel tubing is
preferred.
Four 1/4" threaded fasteners to mount the unit to the trailer.
One quart of DOT 3, DOT 4, or DOT 5 brake uid (from a new
sealed container).
One emergency breakaway kit - must include a 12 volt, 9 amp
hour (minimum) battery.
Wire (see Electrical Schematic, page 4.)
Location of the Dexter DX Series brake actuator is at the discretion
of the trailer manufacturer or owner. When selecting the location, the
following items should be considered:
1. The shorter the wiring between the unit and the electrical power
source, the smaller the voltage drop.
2. The unit should be located so that the electrical wiring and
brake lines can be neatly routed directly to the towing vehicle
and trailer brakes. Special care should be taken to minimize
the number of bends and ttings in the brake line circuits.
3. An emergency breakaway kit must be located on the trailer so
that the trailer breakaway cable can be easily attached to the
towing vehicle.
4. The Dexter DX Series brake actuator is powered from the
electrical system on the tow vehicle. In order for the unit to
function properly, it must have adequate electrical power (see
Electrical Schematic, page 4.)
5. The Dexter DX Series brake actuator should not be placed in an
area where it is susceptible to damage from trailer loads, road
Scan to view DX Series
Actuator Installation Video
Introduction
CAUTION
Dexter DX Series systems should only be installed by a qualified
technician.
This manual has been provided to guide you through the process of
installing, operating, and maintaining your Dexter DX Series electrically
controlled hydraulic brake actuation device (also referred to as DX Series
brake actuator). This electrically powered unit has been designed and
manufactured to give safe, reliable power to your hydraulic trailer brakes.
CAUTION
Please review and understand all installation manual instructions
before beginning installation. Many steps are sequential so it is
necessary to complete all elements as instructed.
!
CAUTION
This is the safety alert symbol. It is used to alert you to potential
injury hazards. Obey all safety messages that follow this symbol to
avoid possible injury or death.
Please visit www.dexteraxle.com
for current warranty information.

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DX SERIES SERVICE MANUAL
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debris, or from being stepped on. Failure to protect the actuator
from damage can cause the unit to malfunction and void the
Dexter warranty.
Mounting consideration should be given to the following:
1. The unit must be level, with the ller neck up.
2. It is the responsibility of the installer to provide necessary
fasteners for attachment of the actuator to the trailer.
3. Mount unit where it will not be submerged in water.
4. Mounting near the hitch is preferred. Do not mount near the
trailer axles or rear of the trailer.
CAUTION
The Dexter DX Series brake actuator contains sensitive electronics
that must be protected. Drilling additional holes in the housing,
electrostatically painting, or welding anywhere on the unit will
damage the unit making it inoperable and will void the manufacturer’s
warranty. Always remove the unit from the trailer before doing any
welding repair or modifications to the trailer structure.
Connect the trailer brake lines to the actuator as follows:
1. Remove the rubber or plastic plug from the 3/16” inverted are
brake port.
2. Brake line must be compatible with DOT 3, DOT 4, or DOT 5
brake uid.
3. Flush existing brake system and lines until they are free of any
contaminants using DOT 3, DOT 4, or DOT 5 brake uid prior to
connecting to the Dexter DX Series brake actuator.
4. Connect the brake line from the trailer brakes to the 3/16”
inverted are tting on the actuator. Do not tighten the 3/16”
brake line adapter more than the 22 Ft. Lbs. used at factory
installation.
CAUTION
Do not overll uid reservoir. Fluid will expand. Max ll level is
3/8” below bottom of ller neck.
.375”
Air Gap
Fill the unit with DOT 3, DOT 4, or DOT 5 brake uid, while maintaining a
3/8” air gap below the ller neck.
CAUTION
Always use new DOT 3, DOT 4, or DOT 5 brake fluid from a sealed
container. Never attempt to reuse old or dirty fluid. Do not overfill
the unit. Take care to protect painted surfaces from contact with
the brake fluid. Wash off any spilled brake fluid.
Mount the emergency breakaway switch and emergency breakaway
battery on the trailer, as detailed in the instruction sheets provided with
the emergency breakaway kit.
Bolt Mounting Pattern
9-13/16"
2-1/2"
(63.5mm)
(250mm)
Electrical Wire Colors and Function
CAUTION
Only use a maintained battery with no less than 12.5v (see
battery chart below). Testing with a battery charger or other
device will cause loss of function.
100%
12.73v
80%60%40%20%0%
12.5v12.24v11.96v11.66v10.5v
% Battery Charge Chart
CAUTION
Undersized wire will increase electrical resistance and will prevent
proper operation of this unit.
BLACK – 30 amp 12 volt supply from tow vehicle*
BLUE – Output from electronic brake controller in tow vehicle
WHITE – Trailer and tow vehicle ground
YELLOW – Cold side of breakaway switch
It is important that wire lengths for the BLACK power lead and WHITE
ground lead be no longer than 25 feet from the DX Series brake
actuator to the supply power (i.e. on board trailer battery or the tow

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vehicle battery). The DX Series brake actuator needs to be located as
close as possible to the battery near the front of the trailer. DO NOT
mount the DX Series brake actuator near the trailer axles or rear of
the trailer. Having the wire length longer than 25 feet may cause issues
with performance and the normal operation of the unit.
It is critical that the BLACK power lead and WHITE ground lead from
the tow vehicle to the input of the actuator are sized and properly
terminated (i.e. dedicated 30-40* amp circuit on the tow vehicle – 12
gauge wire minimum). 10-gauge wire is recommended to optimize
performance. Consult the SAE wiring guidelines for proper trailer
electrical harness design.
*Low temperature applications below 0°F require a 40-amp circuit.
The blue wire from the electric brake controller is connected through
the trailer plug to the blue wire on the actuator. The yellow wire from
the DX Series brake actuator is connected to the cold side of the trailer
emergency breakaway switch. Under no circumstances should the
actuator blue wire and the DX Series brake actuator yellow wire be
connected together, nor should the blue wire ever be grounded.
The white wire is connected to the trailer ground and also connected
to the tow vehicle ground through the trailer plug. The black wire is
connected to the +12V power line from the tow vehicle. The black wire
can also be connected to large on-board batteries. The black wire
is connected to the small breakaway battery only through the black
wire on the charger of the breakaway battery. When connecting and
disconnecting the black wire, sparking may occur. This is a normal
occurrence.
Electrical Installation Requirements
Requires an Electric Brake Controller – The Dexter DX Series brake
actuator is intended to be used with an electric brake controller in the
tow vehicle. The unit will operate with a wide variety of controllers but
provides optimum performance when used with a Dexter electric brake
controller . The electric brake controller must have an output capacity of at
least 5 amps for proper operation of the Dexter DX Series brake actuator.
Although compatible, time based brake controllers are not recommended.
CAUTION
It is the responsibility of the end user to ensure that their electric
brake controller is compatible with the Dexter DX Series brake
actuator. Dexter attempts to provide compatibility with most
controllers available, but is unable to anticipate design changes
that might be introduced by the various controller manufacturers.
Electrical Connections – Make sure all electrical connections are
clean, dry, weather tight, and secure to prevent damage to the wiring
from dragging or becoming entangled with foreign objects. A dedicated
ground connection between the tow vehicle and trailer is also required.
Breakaway Battery Requirement – To comply with federal
requirements, the trailer must be equipped with a breakaway switch and
battery. The breakaway battery needs to have a minimum capacity of 9
amp hours and needs to be maintained in a fully charged condition at
all times. The breakaway battery should be checked for proper charge
level before every use.
Electrical Schematic
Trailer
Plug
From Tow
Vehicle Controller
(Typically Blue)
+12 Volt
40 Amp
Circuit From
Tow Vehicle
Ground From
Tow Vehicle
Break-
Away
Switch
Lanyard
Connect
To The
Trailer
Ground
Circuit
Hydraulic
Line
Charger
YELLOW
BLUE
BLACK
WHITE
BLUE
BLACK
WHITE
BLACK
WHITE
ORANGE/BLACK
LIGHT
BLUE/
YELLOW
Note: Either an onboard or breakaway
battery may be used.
ADAPTER
058-036-00
(IF REQUIRED)
Breakaway
Battery
12 Volt
9 Amp Hour
Minimum

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DX SERIES SERVICE MANUAL
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Charging the Breakaway Battery – The breakaway battery must be
kept fully charged at all times in order to function properly. Use only
those breakaway battery kits that include a charging device. Do not
attempt to charge the breakaway battery directly from the tow vehicle
without the appropriate charging device.
Test Electrical Operation
1. Attach the trailer to the towing vehicle. Do not connect trailer
plug to tow vehicle until step #2 is completed.
2. Pull the breakaway switch. The Dexter DX Series brake actuator
should run. If the unit does not run, check breakaway battery
condition and system wiring. Reset the breakaway switch, which
will turn the unit off. Note: When the unit is running, the motor
will generate a “hum” that changes pitch as the unit builds
pressure. This is normal.
3. Connect trailer plug to tow vehicle.
4. Turn the ignition switch on and turn the electric brake controller
on. Inertia type controllers will often require the vehicle to be
moving in order for the Dexter DX Series brake actuator to
come on by means of the brake pedal. If the unit does not run,
check system wiring.
5. Apply the controller manual slide. The Dexter DX Series brake
actuator should run and brake lights come on.
!
CAUTION
Testing the Dexter DX Series brake actuator confirms that it is
operating. It DOES NOT confirm that the brakes are operating
properly. Regular inspection, adjustment, and maintenance of
the brakes, lines, hoses, drums, discs, fluid, and other associated
components is necessary to ensure proper brake operation.
6. Some brake controllers require a certain speed to actuate
the trailer brakes via the brake pedal. This occurrence will not
produce a high enough signal voltage to actuate the trailer
brakes when the vehicle is at a standstill. Please contact your
vehicle/controller manufacturer for further details.
7. When the tow vehicle brakes are released, the unit may
continue to run for a few seconds.
Bleeding and Brake Adjustment
1. It typically is much easier to bleed the brakes with two people
working together.
2. Special care must be taken to insure that the Dexter DX Series
brake actuator does not run out of brake uid. Check the uid
level frequently during the bleeding process.
3. Block the wheels on the trailer and towing vehicle.
4. If the trailer is equipped with drum brakes, check that the brake
running clearances are properly adjusted consistent with the
trailer manufacturer’s recommendations.
CAUTION
Failure to properly adjust the brakes on trailers equipped with drum
brakes can result in slower response time of the Dexter DX Series
brake actuator.
5. Install plastic tubing onto the bleeder screw of the wheel
cylinder/caliper farthest from the Dexter DX Series brake
actuator. If towed vehicle has multiple axles, always start with
the rear axle rst.
6. Immerse the free end of the plastic tube in a clean clear
container partially lled with brake uid.
7. Open the bleeder screw one half turn on the wheel cylinder/
caliper.
8. To activate the Dexter DX Series brake actuator, turn the ignition
switch on and use manual slide on the brake controller.
9. Watch the free end of the bleeder hose for air bubbles escaping
into the clear container. Continue to bleed the wheel cylinder/
caliper until the uid becomes clear and free of bubbles.
CAUTION
Do not run the Dexter DX Series brake actuator without adequate
brake fluid in the reservoir as it may damage the unit and void the
warranty. Check all bleeder screws to ensure that they are securely
closed and do not leak.
10. Tighten the bleeder screw, turn off the Dexter DX Series brake
actuator, and remove plastic tubing from the bleeder screw.
Bleeding of the wheel cylinder/caliper is now complete.
11. Rell the Dexter DX Series brake actuator with brake uid.
12. Continue the above process (steps 5 through 11) on the next
farthest brake away from the actuator.
13. Repeat these steps until all the brakes have been bled.
14. New trailers with disc brakes should be bled at least twice.
Any air in the brake system will cause brake delay with an E/H
brake actuation system.
CAUTION
Ensure no debris enters the fluid reservoir tank while the cap is
removed. Failure to do so may have an effect on product life.

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Sleep Mode
DX Series E/H Actuator will automatically go into sleep mode after
5 hours of not receiving input from blue (brake controller) or yellow
(breakaway switch) wire to conserve power consumption on trailer
battery. The sleep mode timer will reset if the power/ground is removed.
The DX Series E/H Actuator will wake up from this sleep mode on
the rst brake request signal from the tow vehicle’s brake controller
(blue wire). Using the breakaway switch to wake up the DX Series E/H
Actuator from sleep mode is not recommended.
Disconnect battery from DX Series E/H Actuator if trailer is going to be
stored for longer than one month.
Electric Controller Unit Testing/Adjusting
1. Adjust the gain setting on the electric brake controller to a mid
range setting.
2. Drive vehicle at 10 to 15 m.p.h.
3. Apply the brakes. If braking is too severe, adjust the gain
setting down to decrease pressure and retest. If braking is
inadequate, increase the gain setting on the electric brake
controller and retest.
4. Repeat this process until the brakes respond appropriately.
!
CAUTION
The appropriate pressure setting will vary depending on the weight
of the load being transported on the trailer, weather conditions
and road conditions. The “Testing and Adjustment of Electronic
Controller Unit” procedure should be repeated each time the
trailer is used. Failure to properly adjust the Dexter DX Series brake
actuator may result in poor brake performance and could result in
serious or fatal injuries and/or property damage.

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DX SERIES SERVICE MANUAL
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Troubleshooting Guide
Unit will not run or brakes are slow to respond. To determine if the unit
is functioning properly, perform the checks outlined below
1. Verify that the trailer and tow vehicle are wired according to the
electrical schematic shown in “Electrical Requirements”.
2. Cycle power to reset the unit. If the trailer is equipped with an
on-board battery, disconnect the black power wire to the DX
Series E/H Actuator for 15 seconds and reconnect to the power
source. Re-test unit. If the unit does not have an on-board
battery, please disconnect the unit from the tow vehicle and
then reconnect after 15 seconds.
3. Re-bleed the trailer brakes. Any air in the trailer brake system
causes brake delay.
4. If the trailer is equipped with drum brakes, re-adjust the drum
brakes to the trailer manufacturer’s recommended running
clearance.
5. Trailer wiring that is too small can cause slow response (see
section on Electrical Installation Requirements).
6. Slow response can be caused by brake line restrictions. The
trailer brake lines must be at least 3/16” in diameter. Steel
tubing must be used as much as possible. Using too much
exible hose may cause slow brake response.
7. Check to see if the white ground wire runs directly to the
tow vehicle ground. IT MUST NOT BE GROUNDED TO THE
TRAILER ONLY. IT IS IMPORTANT THAT THIS GROUND WIRE
RUNS DIRECTLY TO THE TOW VEHICLE’S BATTERY GROUND. NO
EXCEPTIONS.
8. Detach all wires from the Dexter DX Series brake actuator
leaving the blue, black, white, and yellow wires loose. It is
important that the unit is disconnected from any other wires
going to the towing vehicle or breakaway switch and breakaway
battery. Failure to do so may result in a faulty test.
9. Using a 12 volt battery, connect the white wire to the negative
(-) terminal of the battery.
10. Connect the black wire to the positive (+) terminal of the
battery and the DX Series brake actuator will click once. The
motor should not run. If the motor runs, the DX Series brake
actuator may be defective.
11. Leave the white wire connected to the negative (-) terminal of
the battery.
12. Connect the blue and black wires together to the positive (+)
terminal of the battery.
13. The motor should run and the unit should pressurize. If this
does not occur, the unit may be defective.
14. Leave the white wire connected to the negative (-) terminal of
the battery.
15. Connect only the yellow wire to the positive (+) terminal of the
battery.
16. The motor should run and the unit should pressurize. If this
does not occur, the unit may be defective.
17. If the unit checks OK, reconnect the wires leading to the trailer
plug and repeat steps 8 through 14 at the trailer plug. If you do
not get the same results as before, the problem is in the trailer
wiring or the electronic brake controller.
Using the breakaway system to troubleshoot a unit that is not
operating correctly
1. With a fully charged breakaway battery and trailer plug
disconnected, pull the breakaway switch on the trailer.
a. If the unit runs and builds pressure, the breakaway system is
functioning properly.
b. If the unit runs and builds pressure when the breakaway
switch is pulled but will not function under normal operating
conditions, the problem most likely is a defective electric
brake controller or defective wiring between the tow vehicle
and Dexter DX Series brake actuator.
c. If the unit runs but will not build pressure when the
breakaway switch is pulled, the Dexter DX Series brake
actuator may be malfunctioning.
d. If the unit does not run, measure the DC voltage between the
white wire and the yellow wire. If the voltage is less than 12
volts, either the breakaway switch or the breakaway wiring is
defective.
2. After completing the above steps, reset the breakaway switch
and reconnect the trailer plug.
Trailer brakes too aggressive
1. Reduce the gain setting on the electric brake controller.
2. Check brake adjustment.
Trailer brakes not aggressive enough
1. Increase the gain setting on the electric brake controller.
2. Check brake adjustment.
Aftermarket Kits
Description Kit Number
DX Series brake actuator Fill Cap & Gasket K71-685-00
DX Series Brake Actuator Gaskets K71-688-00
DX Series Compatibility Adapter K58-036-00

NO PART OF THIS MANUAL MAY BE REPRODUCED WITHOUT DEXTER’S PERMISSION. ALL PART NUMBERS,
DIMENSIONS AND SPECIFICATIONS IN THIS MANUAL ARE SUBJECT TO CHANGE WITHOUT NOTICE.
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