C.E. Niehoff & Co. C651/C654 Troubleshooting Guides - Manual (Page 3)

Page 3
TG0010C
D. Basic Troubleshooting
1. Inspect charging system components
for damage
Check connections at B– cable, B+ cables,
and regulator harness. Repair or replace any
damaged component before troubleshooting.
2. Inspect 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. In addition, open circuit voltages
must be within ± 0.2 V.
4. Connect meters to alternator
Connect meters as shown in Figure 3, page 4.
5. Operate vehicle
Observe charge voltage.
If charge voltage is above
16 V on either high or low
battery, 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.
Regulator setpoints indicate two different voltage
measurements for this system. First setpoint
is sum of low battery and high battery voltage
measurements. Second setpoint is voltage
measured across low battery only.
If voltage is at or below regulator setpoint, let
charging system operate for several minutes to
normalize operating temperature.
6. Observe charge volts and amps in each circuit
Charge voltage should increase and charge amps
should decrease. If charge voltage does not
increase within ten minutes, continue to next
step.
7. Batteries are considered fully charged if charge
voltage is at regulator setpoint and charge amps
remain at lowest value for 10 minutes.
8. If charging system is not performing properly,
go to Chart 4, page 7.
CAUTION
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
setpoint.
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.
Check:defective regulator.
Go to Chart 3, page 6.
Low Voltage Output
High Voltage Output
No Voltage Output
C. Preliminary Check-out
Check symptoms in Table 1 and correct if necessary.
A . Tools and Equipment for Job
• Digital Multimeter (DMM)
• Ammeter (digital, inductive)
• Jumper wire
B. Identification Record
List the following for proper troubleshooting:
Alternator model number _______________________
Regulator model number _______________________
Setpoints listed on regulator ____________________
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No 14 V Output
Section 2: Basic Troubleshooting