Dodge RAM 1500 1998 Owner's Manual page 560

DR
LAMPS/LIGHTING - EXTERIOR (Continued)
CONDITION
HEADLAMPS DO NOT
ILLUMINATE
HEADLAMPS ON WITH
IGNITION IN RUN, WITH
HEADLAMP SWITCH
OFF
CONDITION
FOG LAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.
FOG LAMP BULBS
BURN OUT
FREQUENTLY
POSSIBLE CAUSES
1. No voltage to headlamps.
2. No ground at headlamps.
3. Broken connector terminal or
wire splice in headlamp circuit.
4. Faulty or burned out bulb.
5. Integrated Control Module
malfunction.
6. J1850 Bus Communication
7. Front Control Module
Malfunction.
1. Faulty headlamp switch.
2. Diagnostic tool indicates (4.7 -
5.0V) on headlamp switch input to
Instrument Cluster.
3. J1850 Bus Communication.
4. Front Control Module
Malfunction.
FOG LAMP DIAGNOSIS
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 ground.
1. Charging system output too
high.
2. Loose or corroded terminals or
splices in circuit.
LAMPS/LIGHTING - EXTERIOR
CORRECTION
1. Repair open headlamp circuit, refer to
Electrical, Wiring Information.
2. Repair circuit ground, refer to Electrical,
Wiring Information.
3. Repair connector terminal or wire splice.
4. Replace headlamp bulb(s).
5. Refer to appropriate Body Control Module
diagnostics.
6. Verify messages being transmitted by
Instrument Cluster and received by FCM.
7. Refer to appropriate ICM/FCM diagnostics.
1. Replace headlamp switch (review Instrument
Cluster logged faults).
2. Inspect and repair terminals, connectors and
open circuits.
3. Verify messages being transmitted by
Instrument Cluster and received by FCM.
4. Refer to appropriate ICM/FCM diagnostics.
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
Electrical, Charging,
4. Test battery state-of-charge. Refer to
Electrical, Battery System.
5. Load test battery. Refer to Electrical, Battery
System.
6. Test for voltage drop across ground
locations. Refer to Electrical, Wiring
Information.
1. Test and repair charging system. Refer to
Electrical, Charging.
2. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
8L - 5