Caution – C.E. Niehoff & Co. N1326-1 Troubleshooting Guides User Manual
Page 3

Page 3
TG0059A
Section B: Basic Troubleshooting
Basic Troubleshooting
1.
Inspect charging system components for
damage
Check connections at regulator and vehicle
harnesses. Repair or replace any damaged
component before troubleshooting.
2.
Inspect all vehicle battery connections
Connections must be clean and tight.
3.
Determine battery voltages and states 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.
Operate vehicle
Observe charge voltage.
If charge voltage is above
33 volts, immediately shut
down system. Electrical
system damage may occur if
charging system is allowed to
operate at high voltage. Go to
Table 1 at left.
If voltage is at or below regulator setpoint, let
charging system operate for several minutes to
normalize operating temperature.
5.
Observe charge volts and amps
Charge voltage should increase and charge amps
should decrease. If charge voltage does not in-
crease within ten minutes, continue to next step.
6.
Batteries are considered fully charged if charge
voltage is at regulator setpoint and charge amps
remain at lowest value for 10 minutes.
7.
If charging system is not performing properly,
go to Chart 1, page 4.
SYMPTOM
ACTION
TABLE 1—System Conditions
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 set-
point.
Check: defective alternator
and/or regulator.
Check: wrong regulator.
Check: high regulator setpoint.
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
Preliminary Check-out
Check symptoms in Table 1 and correct if necessary.
Tools and Equipment for Job
• Digital Multimeter (DMM)
• Ammeter (digital, inductive)
• Jumper wires
Identification Record
List the following for proper troubleshooting:
Alternator model number ______________________
Regulator model number _____________________
Setpoints listed on regulator ___________________
CAUTION