C.E. Niehoff & Co. C802/C802D/C820 Troubleshooting Guides User Manual
Page 9
Page 9
TG0004E
Section 3: Advanced Troubleshooting
(CONT’D)
Test for battery voltage at both alternator 28 V and 14 V B+ terminals. Does bat-
tery voltage exist at both terminals?
Yes
No
Repair vehicle wiring as necessary. Continue test.
Vehicle charging circuit test is complete. Remove jumper
wire used in testing. Run engine and
re-test charging circuit for operation.
Chart 4 –
C820 – No Alternator Output – Test Charging Circuit
Jumper 28 V B+ terminal on alternator to IGN terminal on regulator. Field coil may take 30 seconds to reach full
power. Touch shaft with steel tool to detect significant magnetism. Is shaft magnetized?
Yes
No
Reconnect harness. Go to energize switch on engine
in IGN circuit. Test for battery voltage going into energize
switch from battery. Does battery voltage exist?
Yes
No
Make sure jumper wire from alternator 28 V B+ terminal
to regulator IGN terminal is still attached.
Test for battery voltage at energize switch IGN terminal con-
nection. Does battery voltage exist at energize switch?
IGN circuit from regulator
to energize switch is good.
Energize switch is defective.
STATIC TEST – ENGINE OFF, BATTERY SWITCH ON, KEY ON
Repair vehicle circuit to
energize switch. Continue test.
Yes
No
Repair vehicle circuit
from IGN terminal on
regulator to energize
switch on engine.
Figure 9 – Alternator-to-Regulator Harness Plug
PIN CONNECTIONS
Pin A
F–
Pin B
SCR Gate
Pin C
B–
Pin D
28 V B+
Pin E
14V B+
T
T
T
T
T
T
T
T
T
T
Yes
Momentarily (1 sec.) connect jumper wire
from pin A in harness plug to B– terminal
on alternator. Spark will occur. Touch steel
tool to shaft to detect significant magnetism.
Is shaft magnetized?
Disconnect jumper wire. Connect DMM red lead
to pin D in alternator-to-regulator harness plug.
Connect black lead to pin C in same plug. Does
battery voltage exist?
Yes
No
Disconnect jumper
wire. Alternator is
defective.
No
Alternator is defective.
T
T
Disconnect jumper wire. Connect DMM red lead
to pin E in alternator-to-regulator harness plug.
Connect black lead to pin C in same plug. Does
battery voltage exist?
Yes
No
Alternator is
defective.
T
Regulator is de-
fective.
T
T
T
Unplug alternator-to-regulator harness. Touch shaft with
steel tool to detect significant magnetism.
Is shaft magnetized?
Yes
No
T
Alternator is defective.
T
T
T