Diagnosis Of Power Window System - GMC G Service Manual

DIAGNOSIS OF POWER WINDOW SYSTEM

PROBLEM
Passenger Window 1. No power at the passenger switch.
Will Not Work, Using
Either Passenger
Switch or Driver
Switch. 2. Passenger switch is not working.
3. Motor has an internal open.
1. No power at the passenger switch.
Passenger Window
Will Not Work Using
the Passenger
Switch. The Window
2. Switch has internal open.
Will Work Using the
Driver Switch.
Passenger Window 1. No power.
Won't Work Using the
Driver Switch.
2. Open in driver switch.
3. Open in harness.
Driver Window Won't 1. Switch won't work.
Work. Passenger
Window Works.
2. Motor has internal open.
3. Motor ground circuit is open.
POSSIBLE CAUSE
CAB ELECTRICAL 8A-29
CORRECTION
1. Ignition switch at RUN or ACC. Check for
voltage at the PNK wire on the passenger
switch. If there is no voltage, find the open
between the switch and the fuse block.
2. With the voltage on the PNK wire at the
switch, move the switch to "UP." There
should be voltage on the DK BLU wire at the
switch. If there is no voltage on the DK BLU
wire, replace the switch.
3. With the window switch moved to the "UP"
position, check for voltage on the DK BLU
wire at the motor. If there is no voltage, find
the open between the switch and the motor. If
there is voltage on the DK BLU wire, back­
probe a jumper ground at the BRN wire at the
motor. If the motor does not run, replace the
motor. If the motor does run, find the open in
the ground circuit. Note: the ground circuit
does run back through the passenger win­
dow "DN" contacts and the driver window
switch "DN" contacts before reaching
ground.
1. Check for voltage on the PNK wire at the
passenger switch. If voltage is not present,
find the open in the circuit between the switch
and the I.P. harness connector.
2. If voltage is present, replace the switch.
1. Check driver window action. If the driver win­
dow works, power is at the switch.
2. With the driver switch moved to "UP," check
for voltage on the DK BLU wire at the driver
switch. If voltage is not present, replace the
switch.
3. With voltage present on the DK BLU wire at
the driver switch, find the open between the
driver switch and the passenger switch.
1. Switch moved to "UP." Check for voltage at
the DK BLU wire at the switch. If voltage is
not present, replace the switch.
2. Switch moved to "UP." Check for voltage on
the DK BLU wire at the motor. If voltage is
present, backprobe a jumper ground at the
BRN wire at the motor. If the motor won't run,
replace the motor.
3. Backprobe a jumper ground at the BRN wire
at the motor. Move the driver switch to "UP." If
the motor runs, find the open in the ground
circuit.
GMTB-0890-2L