Diagnosis Of Wiper (P-Models) - Off Vehicle; Diagnosis Of Windshield Washer - R/V And G-Van - GMC G Service Manual

8A-36 CAB ELECTRICAL
DIAGNOSIS OF WIPER (P-MODELS) —
PROBLEM
Wiper Not Working or
Intermittent
2. Poor solder connections at terminal board.
3. Loose splice joints at brush plate.
4. Brushes binding in brush holder.
Wiper Will Not Shut-
Off. Wiper Has
Normal "Hi" and "Lo"
Speed
Wiper Will Not Shut
Off. Wiper Has "Lo"
Speed Only
Wiper Will Not Shut
Off. Wiper Has "Hi"
Speed Only
Wiper Shuts Off —
But Not In Park
Position
"Hi" Speed Too Fast
DIAGNOSIS OF WINDSHIELD WASHER —
PROBLEM
Washer Fluid Does
Not Spray on the
Windshield
OFF VEHICLE
POSSIBLE CAUSE
1. Broken or damaged gear train (only if not
working).
5. Open circuit in armature.
1. Faulty part switch.
2. Grounded red lead wire.
1. Grounded shunt field coil.
2. Grounded black wire.
1. Open circuit in shunt field coil.
2. Open circuit in black wire.
Park switch defective or contacts dirty.
Resistor defective.
R/V AND G-VAN
POSSIBLE CAUSE
1. No fluid.
2. Clogged jets.
3. Clogged filter in the reservoir.
4. Washer motor is not running.
CORRECTION
1. Replace gears as required.
2. Resolder wires at terminals.
3. Recrimp or solder splice joints.
4. Clean holder or replace brush, spring or
brush plate assembly.
5. Replace armature.
1. Replace terminal board assembly.
2. Repair short circuit in red wire.
1. Replace frame and field assembly.
2. Repair short circuit in black wire.
1. Replace frame and field assembly.
2. Repair broken wire or poor solder
connection.
Replace terminal board assembly or clean
contacts.
Replace terminal board assembly.
CORRECTION
1. Check the fluid reservoir. Refill, if necessary.
2. Using a fine pin, carefully clear the jets.
3. Remove the filter and back flush it. Also clean
the reservoir.
4. Check for power on the WHT wire at the
motor. If there is no power, and the wipers
work, find the open in the power circuit. If
there is power, check the PNK wire at the
washer motor for ground. If the ground circuit
is good, replace the washer motor.
GMTB-0893-2L
GMTB-0891-2L