Diagnosis Of The Turn Signal And Hazard Systems - GMC G Service Manual

DIAGNOSIS OF THE TURN SIGNAL
PROBLEM
Him Signals Not 1.
Working On One Side
2.
3.
4.
Hirn Signals Not 1.
Working
2.
3.
Hazard Warning Not 1.
Working
2.
3.
AND HAZARD SYSTEMS
POSSIBLE CAUSE
Bulb(s) burned out (flasher cannot be heard).
Open wiring or loose ground connector.
Improper bulb or defective turn signal switch.
Short to ground. (Flasher can be heard, no
bulbs operate).
Blown turn signal fuse.
Defective flasher (located in convenience
center near steering column).
Loose connection.
Blown stop-hazard fuse.
Faulty hazard warning flasher. (Located in
the convenience center).
Open in the wiring or a defective turn signal
switch.
CHASSIS ELECTRICAL 8B-5
CORRECTION
1. Turn the hazard warning system "ON." If one
or more bulbs are inoperative, replace the
bulbs as necessary.
2. Turn the hazard warning system on. If one or
more bulbs are inoperative, use the test lamp
and check the circuit at the bulb socket. If the
test bulb lights, repair the open ground con­
nection. If not, repair the open wiring be­
tween the bulb socket and the turn signal
switch.
3. Turn the hazard warning system on. If all the
front lamps and rear lamps operate, check
for an improper bulb (see bulb chart). If the
bulbs are OK, replace the defective turn sig­
nal switch.
4. Locate and repair the short to ground by
disconnecting the front and rear circuits
separately.
1. Turn the hazard warning system on. If all the
lamps operate, replace the blown fuse. If the
new fuse blows, repair the short to ground
between the fuse and the lamps.
2. If the turn signal fuse is OK and the hazard
warning system will operate the lamps, re­
place the defective turn signal flasher.
3. Secure the steering column connector.
1. Switch the turn signals "ON." If the lights
operate, replace the stop-hazard fuse if
blown. If the new fuse blows, repair the short
to ground. (Could be in stop lamp circuit).
2. If the stop-hazard fuse is OK, switch the turn
signals on. If the lamps operate, replace the
defective hazard flasher.
3. Using the test lamp, check the brown wire in
the turn signal steering column connector. If
the test bulb does not light, repair the open
circuit betwen the flasher and the connector.
If the test lamp indicates power on the brown
wire and connection is good, use a test lamp
to check the output terminals (It. blue, blue,
yellow and dark green wires).
GMTB-0850-2L