Pontiac FIREBIRD 1972 Service Manual page 1288

12-18 1972 PONTIAC SERVICE MANUAL
FOR VOLTAGE C H E C K S CONNECT
12 VOLT TEST BULBS BETWEEN
RT.
R E A R SIDE
GROUND A N D TEST POINT BEING
M A R K E R LP.
CHECKED FUSE BLOCK
CONNECTOR
RT. PARK &
M A R K E R LP.
B U L K H E A D
LIGHT SWITCH
CONNECTOR
BLKILT. B L U E
T U R N SIG. LP.
LT.
SIDE
M A R K E R LP.
BODY CONNECTOR T R U N K LT. R E A R SIDE
CONNECTOR M A R K E R LP.
Tail lamp fuse blown.
Loose connection.
Open wiring.
Multiple bulb burnout.
Defective light switch.
Fig. 12-20 Side Marker Lamp Circuit
BOTH SIDES INOPERATIVE
*Replace fuse. If new fuse blows, repair short
to ground in brown wire circuit between fuse
panel through light switch to lamps.
*Secure connector at light switch.
*If test bulb does not light on either side of
fuse, repair open circuit between fuse panel and
battery. (Possible open fusible link.) If test
bulb lights at light switch brown wire terminal
# 5 , repair open wiring between light switch and
lamps.
*If test bulb lights at lamp socket brown
wire terminal replace bulbs.
*If test bulb lights at light switch terminal
#4 (browdwhite) but not at terminal # 5
(brown), replace defective light switch.
*See tail lamp circuit (Fig. 12-2 1).
BACK-UP LAMPS DIAGNOSIS
ONE LAMP INOPERATIVE OR INTERMITTENT
CAUSE
Open ground connection.
L&se connection.
Bulb out.
CORRECTION
*Repair bulb ground circuit.
*Tighten connectors.
Replace bulb.