C.E. Nierhoff & Co C815 User manual
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C715/C716 Alternators
Troubleshooting Guide
C.E. Niehoff & Co.
Page 1TG7B
CONTENTS
Section 1:Wiring .................................................................2
Section 2: Basic Troubleshooting.....................................3
Section 3: Advanced Troubleshooting .............................4
Battery Charging Conditions
The following conditions may be observed during cold-
start voltage tests until temperatures of electrical system
components stabilize. The time it takes to reach optimum
voltage and amps will vary with engine speed, load, and
ambient temperature.
Maintenance/Low Maintenance Lead-Acid Battery:
Traditional lead acid batteries require lowest charge volt-
age of all vehicle battery chemistries. Battery cells must
be maintained by periodically topping off with distilled
water as required.
Maintenance-free Lead-Acid Battery:
Maintenance-free batteries are similar to Maintenance/
Low Maintenance batteries, but may require slightly higher
charge voltage.
Deep-cycle/Marine Maintenance-free Battery:
Charge acceptance of these batteries may display charac-
teristics similar to maintenance-free batteries and may
charge faster due to generally lower capacity relative to
size.
AGM (Absorbed Glass Mat) Maintenance-free Battery:
These dry-cell batteries respond better than standard
maintenance-free batteries. If battery state of charge
(SOC) drops to 75% or less, batteries should be
recharged to 95% or higher separately from engine charg-
ing system to avoid damaging charging system
components and to provide best overall performance.
Charge acceptance of these batteries may display
charac-
teristics similar to maintenance batteries, but may require
higher charge voltage and will draw signicant current (<100
amps) when under 50% SOC.
Lithium Battery:
Lithium batteries have unique charging characteristics that
differ from lead acid. These batteries require charging
systems congured specically for lithium battery chemis-
tries. Contact CEN for more information on lithium battery
charging systems and components.
Voltage testing:
• Set meter to proper scale and type (AC or DC).
• Be sure to zero the meter scale or identify the meter
burden by touching meter leads together. Meter burden
must be subtracted from nal reading obtained.
• Be sure the meter leads touch source area only.
Prevent short circuit damage to test leads or source by
not allowing meter leads to touch other pins or exposed
wires in test area.
• Be sure to use CEN tools designed especially for trou-
bleshooting CEN alternators when available.
Resistance (ohm) testing:
• Set meter to proper scale.
• Be sure to zero the meter scale or identify the meter
burden by touching meter leads together. Meter burden
must be subtracted from nal reading obtained.
• Be sure meter leads touch source area only. Allowing
ngers or body parts to touch meter leads or source
during reading may alter reading.
• Be sure reading is taken when source is at 70ºF. Read-
ings taken at higher temperatures will increase the
reading. Conversely, readings taken at lower tempera-
tures will decrease the reading.
• Be sure to test directly at the source. Testing through
extended harnesses or cable extensions may increase
the reading.
• "OL" as referenced in this document refers to open cir-
cuit: "innite" resistance, typically in very high kilo- or
megaohm range depending on meter and settings.
Diode testing:
• Diodes allow current to ow in one direction only. Typi-
cal voltage drop in forward bias can range from 0.1-
0.85V. Meter should read OL in reverse bias. Check
meter user manual for meter-specic testing guidelines.
Voltage drop testing:
• Measure voltage between B+ on alternator or power
source and B- (ground) on alternator or source. Record
reading. Move to batteries or other power source and
measure again between B+ and B- terminals on battery
or other power source. The difference between the two
readings represents voltage lost within circuit due to,
but not limited to, inadequate cable gauge or faulty con-
nections.
• Voltage drop measurements must be taken with all elec-
trical loads or source operating.
Dynamic/Live testing (Connecting power and ground to
component to test operation/function out of circuit):
• Connect jumper leads directly and securely to power
source contacts of component being tested.
• Make any connection to power and ground at power
supply or battery source terminals. Do not make con-
nection at component source terminals, as that may
create an arc and damage component source terminals.
Testing Guidelines
Professional service technicians rely on the following
guidelines when testing electrical components.
TG0007A
C. E. Niehoff & Co.
BRUSHLESS ALTERNATORS
The C715C715
C715C715
C715 alternator (14 V, 360 A) and C716C716
C716C716
C716 alterna-
tor (14 V, 400 A) are internally rectified. All windings
and current-transmitting components are non-
moving, so there are no brushes or slip rings to wear
out. This unit is externally energized through either
an ignition switch or an energize switch (commonly
an oil pressure switch), which activates regulator.
Field coil is then energized. Regulator maintains
alternator output voltage at regulated setting as
vehicle electrical loads are switched on and off.
Alternator output current is self-limiting and will not
exceed rated capacity of alternator.
A2-128 regulator used with all units has R terminal
for optional AC voltage tap. A 15.5 V regulator set-
point is available for battery isolator applications.
Electromagnetic interference (EMI) is suppressed with
internal filters to acceptable levels defined by the
Society of Automotive Engineers (SAE) specification
J1113/41. A2-128 regulator will not reduce EMI from
sources such as antennas, poor cable routing prac-
tice, or other electronic devices that cause EMI. If EMI
continues, consult an electromagnetic compliance
(EMC) specialist to determine EMI source.
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Section 1: Wiring Diagram
Page 2 TG7B
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C. E. Niehoff & Co.
BRUSHLESS ALTERNATORS
1. Inspect charging system componentsInspect charging system components
Inspect charging system componentsInspect charging system components
Inspect charging system components
for damagefor damage
for damagefor damage
for damage
Check connections at B– cable, B+ cable, and
regulator harness. Repair or replace any dam-
aged component before troubleshooting.
2. Inspect vehicle battery connectionsInspect vehicle battery connections
Inspect vehicle battery connectionsInspect vehicle battery connections
Inspect vehicle battery connections
Connections must be clean and tight.
3. Determine battery voltage and state of chargeDetermine battery voltage and state of charge
Determine battery voltage and state of chargeDetermine battery voltage and state of charge
Determine battery voltage and state of charge
If batteries are discharged, recharge or replace
batteries as necessary. Electrical system cannot
be properly tested unless batteries are charged
95% or higher.
4. Determine if battery isolator is usedDetermine if battery isolator is used
Determine if battery isolator is usedDetermine if battery isolator is used
Determine if battery isolator is used inin
inin
in
charging circuitcharging circuit
charging circuitcharging circuit
charging circuit
Check vehicle wiring diagram. If so, you must
jumper out isolator before troubleshooting. See
Chart 1 on page 4 for details.
5. Connect meters to alternatorConnect meters to alternator
Connect meters to alternatorConnect meters to alternator
Connect meters to alternator
Connect red lead of DMM to alternator B+
terminal and black lead to alternator B–
terminal. Clamp inductive ammeter on B+ cable.
6. Operate vehicleOperate vehicle
Operate vehicleOperate vehicle
Operate vehicle
Observe charge voltage.
If voltage is at or below regulator setpoint, let
charging system operate for several minutes to
normalize operating temperature.
7. Observe charge volts and ampsObserve charge volts and amps
Observe charge volts and ampsObserve charge volts and amps
Observe charge volts and amps
Charge voltage should increase and charge amps
should decrease. If charge voltage does not
increase within ten minutes, continue to next
step.
8. BatteryBattery
BatteryBattery
Battery is considered fully charged if charge
voltage is at regulator setpoint and charge amps
remain at lowest value for 10 minutes.
9. If charging systemIf charging system
If charging systemIf charging system
If charging system is not performing properly,
go to Chart 1, page 4.
Check: loose drive belt; low
battery state of charge.
Check: current load on
system is greater than
alternator can produce.
Check: defective wiring or
poor ground path; low
regulator setpoint.
Check: defective alternator
and/or regulator.
Check: wrong regulator.
Check: high regulator set-
point.
Check: defective regulator.
Check: alternator.
Check: broken drive belt.
Check: battery voltage at
alternator output terminal.
Check: defective alternator
and/or regulator.
Low Voltage Output
High Voltage Output
No Voltage Output
Check condition of items in Table 1 and correct if
necessary.
• Digital Multimeter (DMM)
• Ammeter (digital, inductive)
• CEN Regulator Bypass Adapter A10-129
• Jumper wire
• 12 V test light
Complete the following for proper troubleshooting:
Alternator model number ______________________
Regulator model number _______________________
Setpoints listed on regulator ___________________
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Section 2: Basic Troubleshooting
Page 3TG7B
Page 4 TG0007A
C. E. Niehoff & Co.
BRUSHLESS ALTERNATORS
Section 3: Advanced Troubleshooting
Yes No
For “no voltage output” condition: • with enerener
enerener
energize switchgize switch
gize switchgize switch
gize switch, go to Chart 2, page 5.
• with ignition switchignition switch
ignition switchignition switch
ignition switch, go to Chart 3, page 6.
Is there a battery isolator in the system?
Chart 1 – System Circuit
Install temporary jumper between one battery terminal and
alternator terminal on isolator. Use minimum 12 AWG wire.
Do not operate charging system more than two
minutes with jumper installed. Charging system
voltage will be abnormally high and damage other components.
START HERE
CAUTION
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Section 3: Advanced Troubleshooting
Page 4 TG7B
TG0007A
C. E. Niehoff & Co.
BRUSHLESS ALTERNATORS
Test for battery voltage at B+ terminal on alternator to ground, then at F+ terminal on regula-
tor to ground. Does battery voltage exist?
Yes No
Repair vehicle wiring as necessary. Continue test.
Vehicle charging circuit test is complete.
Remove jumper wire. Run engine and
re-test charging circuit for operation.
Chart 2 – No Alternator Output – EnerEner
EnerEner
Energize Switchgize Switch
gize Switchgize Switch
gize Switch – Test Charging Circuit
Jumper B+ terminal on alternator to E terminal
on regulator. Touch shaft with steel tool to detect
significant magnetism. Is shaft magnetized?
Yes No
Go to energize switch on engine in E circuit.
Test for battery voltage going into energize switch
from battery. Does battery voltage exist?
Yes No
Make sure jumper wire from alternator B+
terminal to regulator E terminal is still attached.
Test for battery voltage at energize switch E
terminal connection. Does battery voltage exist
at energize switch?
E circuit from regulator
to energize switch is
good. Energize switch is
defective.
Repair vehicle circuit to
energize switch. Continue test.
Yes No
Repair vehicle circuit
from E teminal on
regulator to energize
switch on engine.
Yes
Unplug alternator-to-regulator harness. Plug CEN
Regulator Bypass Adapter A10-129 into harness
plug. Make sure black lead does not touch
ground. Clip red lead to B+ terminal on alternator.
(If Adapter is not available, connect jumper wire
from socket B on harness to alternator B+ termi-
nal.) Does spark occur at alternator B+ terminal?
Disconnect Regulator Bypass Adapter or jumper
wire. Connect DMM red lead to socket E in alter-
nator-to-regulator plug. Connect black lead to
socket A in same plug. Does battery voltage exist?
Regulator is defective.
Yes
No
Disconnect Adapter or jumper
wire. Alternator is defective.
No
Alternator is defective.
Touch black lead to ground on alternator case.
(If Adapter is not available, connect jumper wire
from socket C on harness to ground.) Spark will
occur at ground. Touch steel tool to shaft to
detect significant magnetism. Is shaft magne-
tized?
Yes No
Disconnect Adapter or jumper
wire. Alternator is defective.
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Section 3: Advanced Troubleshooting (cont.)
Page 5TG7B
TG0007A
C. E. Niehoff & Co.
BRUSHLESS ALTERNATORS
Chart 3 – No Alternator Output – Ignition SwitchIgnition Switch
Ignition SwitchIgnition Switch
Ignition Switch – Test Charging Circuit
Jumper B+ terminal on alternator to E terminal
on regulator. Touch shaft with steel tool to detect
significant magnetism. Is shaft magnetized?
Yes No
Disconnect jumper. Apply 12 V test light to
regulator E terminal and ground. Does light
glow brightly?
Yes No
Run vehicle. Does charge voltage exist?
System
operating
normally.
Repair wiring or
ignition switch.
Yes No
Jumper B+ terminal on
alternator to regulator
E terminal. Does charge
voltage exist?
Yes No
Repair wiring
or ignition
switch.
Contact CEN
Service
Department
for assistance.
Test for battery voltage at B+ terminal on alternator to ground, then at F+ terminal on regula-
tor to ground. Does battery voltage exist?
Yes No
Repair vehicle wiring as necessary. Continue test.
Yes
Unplug alternator-to-regulator harness. Plug CEN
Regulator Bypass Adapter A10-129 into harness
plug. Make sure black lead does not touch
ground. Clip red lead to B+ terminal on alternator.
(If Adapter is not available, connect jumper wire
from socket B on harness to alternator B+ termi-
nal.) Does spark occur at alternator B+ terminal?
Disconnect Regulator Bypass Adapter or jumper
wire. Connect DMM red lead to socket E in alter-
nator-to-regulator plug. Connect black lead to
socket A in same plug. Does battery voltage exist?
Regulator is defective.
Yes
No
Disconnect Adapter or jumper
wire. Alternator is defective.
No
Alternator is defective.
Touch black lead to ground on alternator case.
(If Adapter is not available, connect jumper wire
from socket C on harness to ground.) Spark will
occur at ground. Touch steel tool to shaft to
detect significant magnetism. Is shaft magne-
tized?
Yes No
Disconnect Adapter or jumper
wire. Alternator is defective.
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Section 3: Advanced Troubleshooting
Page 6 TG7B
TG0007A
C. E. Niehoff & Co.
BRUSHLESS ALTERNATORS
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Page 7TG7B
If you have questions about your alternator or any of these test procedures, or if you need to locate a Factory Authorized Service Distributor, please contact us at:
C. E. Niehoff & Co.• 2021 Lee Street • Evanston, IL 60202 USA
TEL: 800.643.4633 USA and Canada • TEL: 847.866.6030 outside USA and Canada • FAX: 847.492.1242
E-mail us at service@CENiehoff.com
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