HEADLAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS 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 alternator drive
belt.
2. Adjust or replace alternator 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 Z1-ground. 6. Test for voltage drop across Z1-ground
locations. Refer to Group 8W.
HEADLAMP 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.
HEADLAMPS 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 Z1-ground. 2. Test for voltage drop across Z1-ground
locations. Refer to Group 8W.
3. High resistance in headlamp
circuit.
3. Test amperage draw of headlamp circuit.
HEADLAMPS FLASH
RANDOMLY
1. Poor lighting circuit Z1-ground. 1. Test for voltage drop across Z1-ground
locations, refer to Group 8W.
2. High resistance in headlamp
circuit.
2. Test amperage draw of headlamp circuit.
3. Loose or corroded terminals or
splices in circuit.
3. Inspect and repair all connectors and
splices. Refer to Group 8W.
HEADLAMPS DO NOT
ILLUMINATE
1. No voltage to headlamps. 1. Repair open headlamp circuit. Refer to
Group 8W.
2. No Z1-ground at headlamps. 2. Repair circuit ground. Refer to Group
8W.
3. Faulty headlamp switch. 3. Replace headlamp switch.
4. Faulty headlamp dimmer
(multi-function) switch.
4. Replace multi-function switch.
5. Broken connector terminal or wire
splice in headlamp circuit.
5. Repair connector terminal or wire splice.
6. Defective or burned out bulb. 6. Replace bulb.
7. Body controller malfunction. 7. Refer to appropriate body controller
diagnostics.
8L - 2 LAMPS LH
DIAGNOSIS AND TESTING (Continued)
2000 LHS, 300M, CONCORDE AND INTREPID