CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMP SWITCH ON
(LOW BEAMS ON), ONE
LOW BEAM ON AND
BOTH HIGH BEAMS DIM.
1. Headlamp feed circuit shorted to
ground.
1. Check wiring circuit from right headlamp
fuse to headlamp. Repeat for left side.
Trace short circuit in wiring and repair.
Refer to Group W.
HEADLAMP SWITCH ON
(HIGH BEAMS ON), ONE
HIGH BEAM ON AND
BOTH LOW BEAMS DIM.
1. Headlamp feed circuit shorted to
ground.
1. Check wiring circuit from right headlamp
fuse to headlamp. Repeat for left side.
Trace short circuit in wiring and repair.
Refer to Group W.
HEADLAMP SWITCH ON,
ONE HEADLAMP
FILAMENT WILL BE AT
FULL INTENSITY AND ALL
OTHER FILAMENTS ARE
ON AND DIM.
1. Blown headlamp fuse. 1. Trace short circuit and replace fuse.
Refer to Group 8W.
2. Open circuit from headlamp fuse
to headlamp.
2. Repair open headlamp circuit, refer to
Group 8W.
1. HEADLAMPS STAY ON
WITH KEY OUT (DRLM
EQUIPPED VEHICLES).
1. Failed DRLM 1. Replace DRLM.
*Canada vehicles must have lamps ON.
FOG LAMP
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE IDLING OR
IGNITION TURNED OFF.
1. Loose or corroded battery cables. 1. Clean and secure battery cable clamps
and posts.
2. Loose or worn generator drive
belt.
2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system. Refer to
Group 8A,
4. Battery has insufficient charge. 4. Test battery state-of -charge. Refer to
Group 8A.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Group 8A.
6. Poor lighting circuit Z3-ground. 6. Test for voltage drop across Z3-ground
locations. Refer to Group 8W.
FOG LAMP BULBS BURN
OUT FREQUENTLY
1. Charging system output too high. 1. Test and repair charging system. Refer to
Group 8A.
2. Loose or corroded terminals or
splices in circuit.
2. Inspect and repair all connectors and
splices. Refer to Group 8W.
FOG LAMPS ARE DIM
WITH ENGINE RUNNING
ABOVE IDLE
1. Charging system output too low. 1. Test and repair charging system. Refer to
Group 8A.
2. Poor lighting circuit Z3-ground. 2. Test for voltage drop across Z3-ground
locations. Refer to Group 8W.
3. High resistance in fog lamp circuit. 3. Test amperage draw of fog lamp circuit.
8L - 4 LAMPS DN
DIAGNOSIS AND TESTING (Continued)
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