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Section 3: Basic Troubleshooting
Section 3: Basic Troubleshooting
A. Tools and Equipment for Job
• Digital Multimeter (DMM)
• Ammeter (digital, inductive)
• Jumper wires
If no tools are available, monitor LED code.
B. Identi cation Record
List the following for proper troubleshooting:
Alternator model number ______________________
Regulator model number ______________________
TABLE 4 – System Conditions
SYMPTOM
Check: loose drive belt; low bat-
Low Voltage Output
Check: current load on system
Check: defective wiring or poor
Check: defective alternator
High Voltage Output
Check: defective regulator.
Check: alternator.
Check: presence of energize sig-
No Voltage Output
Check: battery voltage at alter-
Check: defective alternator
Page 4
Page 4
ACTION
tery state of charge.
is greater than alternator
can produce.
ground path.
and/or regulator.
nal to IGN terminal on regula-
tor.
nator output terminal.
and/or regulator.
C. Basic Troubleshooting
1.
Inspect charging system components
Check connections at ground cables, positive
cables, and regulator harness. Repair or replace
any damaged component before troubleshooting.
Inspect connections of vehicle batteries
2.
Connections must be clean and tight.
3.
Determine battery type, voltage, and state
of charge
Batteries must be all the same type for system
operation. If batteries are discharged, recharge
or replace batteries as necessary. Electrical
system cannot be properly tested unless batter-
ies are charged 95% or higher. See page 1 for
details.
4.
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.
5.
Operate vehicle
Observe charge voltage.
CAUTION
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
Charge voltage should increase and charge amps
should decrease. If charge voltage does not in-
crease 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 1, page 6.
R
If charge voltage is above
33 volts, immediately shut
down system. Electrical
system damage may occur
if charging system is
allowed to operate at
excessive voltage. Go to
Table 4 at left.
TG0048A
TG48B
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