Dodge RAM 1500 1998 Owner's Manual page 561

8L - 6 LAMPS/LIGHTING - EXTERIOR
LAMPS/LIGHTING - EXTERIOR (Continued)
CONDITION
FOG LAMPS ARE DIM
WITH ENGINE
RUNNING ABOVE IDLE
FOG LAMPS FLASH
RANDOMLY
FOG LAMPS DO NOT
ILLUMINATE
CONDITION
DAYTIME RUNNING
LAMPS DO NOT
OPERATE
POSSIBLE CAUSES
1. Charging system output too low.
2. Poor lighting circuit ground.
3. High resistance in fog lamp
circuit.
1. Poor lighting circuit ground.
2. Variable resistance in fog lamp
circuit.
3. Faulty fog lamp switch (part of
headlamp switch).
4. Loose or corroded terminals or
splices in circuit.
5. Is relay engaging properly?
6. J1850 Bus Communication.
1. Blown fuse for fog lamp.
2. No ground at fog lamps.
3. Faulty fog lamp switch (part of
headlamp switch).
4. Broken connector terminal or
wire splice in fog lamp circuit.
5. Faulty or burned out bulb.
6. Is relay engaging?
7. J1850 Bus Communication.
DAYTIME RUNNING LAMP (CANADA ONLY) DIAGNOSIS
POSSIBLE CAUSES
1. Parking brake engaged.
2. Parking brake circuit shorted
to ground.
3. Headlamp circuit shorted to
ground.
4. FCM, Instrument Cluster not
programed with Canadian
country code.
CORRECTION
1. Test and repair charging system. Refer to
Electrical, Charging.
2. Test for voltage drop across ground
locations. Refer to Electrical, Wiring
Information.
3. Test amperage draw of fog lamp circuit.
1. Test for voltage drop across ground
locations. Refer to Electrical, Wiring
Information.
2. Test amperage draw of fog lamp circuit.
3. Replace headlamp switch.
4. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
5. Verify function of fog lamp relay in IPM.
6. Verify J1850 message (fog lamp info)
transmitted from Instrument Cluster and
received by FCM.
1. Replace fuse. Refer to Electrical, Wiring
Information.
2. Repair circuit ground. Refer to Electrical,
Wiring Information.
3. Replace headlamp switch.
4. Repair connector terminal or wire splice.
5. Replace bulb.
6. Verify function of fog lamp relay in IPM.
7. Verify J1850 message (fog lamp info)
transmitted from Instrument Cluster and
received by FCM.
CORRECTION
1. Disengage parking brake.
2. Check cluster telltale, refer to the appropriate
wiring information.
3. Refer to the appropriate wiring information.
4. Check country code.
DR