Chevrolet 1980 Light Duty Truck Service Manual page 228

3B4-14 STEERING CO LU M N S
CO N D ITIO N
Front or rear turn signal
lights not flashing
Stop light not on when
turn indicated
Turn indicator panel
lights not flashing
SIGNAL SWITCH DIAG NO SIS
POSSIBLE CAUSE
A. Burned out fuse
Burned out or
B.
damaged turn signal
bulb
High resistance
C.
connection to ground
at bulb socket
Loose chassis to
D.
column connector
Disconnect column to
E.
chassis connector.
Connect new switch
into system and
operate switch
by hand.
If turn signal lights
are now on and
flash, turn signal
switch is inoperative.
F. If vehicle lights do
not operate, check
chassis wiring harness
to light sockets for
opens, grounds, etc.
Burned out fuse
A.
Loose column to
B.
chassis connection
C. Disconnect column to
chassis connector.
Connect new switch
into system without
removing old. Operate
switch by hand.
If brake lights work
with switch in the
turn position, signal
switch is defective
D. If brake lights do not
work check connector
to stop light sockets
for grounds, opens,
etc.
A. R ned out bulbs
high resistance to
B.
ground at bulb socket
Opens, grounds in
C.
wiring harness from
front turn signal bulb
socket to indicator
lights
Fig. 3 B 4 -1 5 -T u rn Signal Sw itch Diagnosis C h art C
CORRECTION
A. Replace fuse and
check operation
Replace bulb
B.
Remove or repair
C.
defective connection
and check operation
D. Connect securely and
check operation
E. Replace turn signal
switch.
Repair chassis wiring
F.
as required using
manual as guide
A. Replace fuse and
check operation
B. Connect securely and
check operation
Replace signal switch
C.
D. Repair connector to
stop light circuits
using manual as guide.
Replace bulbs
A.
B. Replace socket
C. Locate and repair as
required. Use shop
manual as guide.
LIG H T T R U C K S ER V IC E MANUAL