Jeep 1996 Grand Cherokee Service Manual page 377

8L - 2 LAMPS
DIAGNOSIS AND TESTING (Continued)
HEADLAMP DIAGNOSIS
HEADLAMP DIAGNOSIS
CONDITION
HEADLAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF
HEADLAMP BULBS BURN
OUT
FREQUENTLY
HEADLAMPS ARE DIM
WITH ENGINE RUNNING
ABOVE IDLE
HEADLAMPS FLASH
RANDOMLY
HEADLAMPS DO NOT
ILLUMINATE
POSSIBLE CAUSES
1. Loose or corroded battery cables.
2. Loose or worn generator drive
belt.
3. Charging system output too low.
4. Battery has insufficient charge.
5. Battery is sulfated or shorted.
6. Poor lighting circuit Z1-ground.
7. Both headlamp bulbs defective.
1. Charging system output too high.
2. Loose or corroded terminals or
splices in circuit.
1. Charging system output too low.
2. Poor lighting circuit Z1-ground.
3. High resistance in headlamp
circuit.
4. Both headlamp bulbs defective.
1. Poor lighting circuit Z1-ground.
2. High resistance in headlamp
circuit.
3. Faulty headlamps switch circuit
breaker.
4. Loose or corroded terminals or
splices in circuit.
1. No voltage to headlamps.
2. No Z1-ground at headlamps.
3. Faulty headlamp switch.
4. Faulty headlamp dimmer
(multi-function) switch.
5. Broken connector terminal or wire
splice in headlamp circuit.
CORRECTION
1. Clean and secure battery cable clamps
and posts.
2. Adjust or replace generator drive belt.
3. Test and repair charging system, refer to
Group 8A,
4. Test battery state-of -charge, refer to
Group 8A.
5. Load test battery, refer to Group 8A.
6. Test for voltage drop across Z1-ground
locations, refer to Group 8W.
7. Replace both headlamp bulbs.
1. Test and repair charging system, refer to
Group 8A.
2. Inspect and repair all connectors and
splices, refer to Group 8W.
1. Test and repair charging system, refer to
Group 8A.
2. Test for voltage drop across Z1-ground
locations, refer to Group 8W.
3. Test amperage draw of headlamp circuit.
4. Replace both headlamp bulbs.
1. Test for voltage drop across Z1-ground
locations, refer to Group 8W.
2. Test amperage draw of headlamp circuit.
Should not exceed 30 amps.
3. Replace headlamp switch.
4. Inspect and repair all connectors and
splices, refer to Group 8W.
1. Repair open headlamp circuit, refer to
Group 8W.
2. Repair circuit ground, refer to Group 8W.
3. Replace headlamp switch.
4. Replace multi-function switch.
5. Repair connector terminal or wire splice.
ZJ