Beohbebewhy

I've got a 2002 Dodge 1500 SLT Quad Cab with a 318 and the headlights are being super stupid. On Low Beams, one headlight will work, on High Beams, the other headlight will work. I have replaced the bulbs, and don't have a clue where to begin trying to fix this. I know if I take it to the Dodge dealership they are going to rape me on it because I have NO idea what could be causing the problem.

Midnight Tech

Sure sounds like it may be in the headlight switch - any chance you might could get one from the salvage yard to try? No use buying a new one to troubleshoot.

dodgemechanic

Here is text straight from the Dodge dealership books-
HEADLAMP SYSTEM
The instrument cluster monitors both the multiplexed headlamp and multifunction switches. The instrument cluster transmits a J1850 bus message to the front control module (FCM) to activate the headlamps. The headlamp system will default to headlamps ON position when ignition switch is ON and when an open or short circuit failure occurs on the headlamp switch input to the instrument cluster. The system will return to normal operation when the open or short is repaired. A fault will be reported by the Instrument Cluster when a failure occurs on the dimmer or headlamp switch input.

If the exterior lamps are ON, and the headlamp switch is in any position other than OFF, with the ignition switch OFF (LOCK) after 5 minutes, the Instrument Cluster transmits a message via J1850 informing the the FCM. The FCM will then turn off the headlamps, park lamps and fog lamps. This feature (load shed) prevents the vehicle battery from being discharged when the vehicle lights have been left ON.

HEADLAMP TIME DELAY SYSTEM
The headlamp time delay system is activated by turning the headlamps ON (high or low beam) while the engine is running, turning the ignition switch OFF, and then turning the headlamp switch OFF within 45 seconds. The system will not activate if more than 45 seconds elapse between ignition switch OFF and headlamp switch OFF. The FCM will allow the headlamps to remain ON for 90 seconds (configurable) before they automatically turn off (If the key is in the ignition during the headlamp time delay mode, then the headlamps including panel dimming will be ON).

LAMP OUTAGE
Here's some extra knowledge for you plus a diag chart-
DIAGNOSIS AND TESTING - LAMPS/LIGHTING - EXTERIOR
WARNING: EYE PROTECTION SHOULD BE USED WHEN SERVICING GLASS COMPONENTS. PERSONAL INJURY CAN RESULT.

CAUTION: Do not touch the glass of halogen bulbs with fingers or other possibly oily surface, reduced bulb life will result. Do not use bulbs other than those indicated in the Bulb Application table. Damage to lamp and/or Daytime Running Lamp Module can result. Do not use fuses, circuit breakers or relays having greater amperage value than indicated on the fuse panel or in the Owners Manual.

When a vehicle experiences problems with the headlamp system, verify the condition of the battery connections, fuses, charging system, headlamp bulbs, wire connectors, relay, multifunction switch, and headlamp switch. Refer to the appropriate wiring information.

Each vehicle is equipped with various lamp assemblies. A good ground is necessary for proper lighting operation. Grounding is provided by the lamp socket when it comes in contact with the metal body, or through a separate ground wire.

When changing lamp bulbs check the socket for loose pin connections and corrosion. Repair as necessary.

When it is necessary to remove components to service another, it should not be necessary to apply excessive force or bend a component to remove it. Before damaging a trim component, verify hidden fasteners or captured edges are not holding the component in place.

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 generator drive belt. 2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system, refer to Electrical, Charging
4. Battery has insufficient charge. 4. Test battery state-of-charge, refer to Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery, refer to Electrical, Battery System.
6. Poor lighting circuit ground. 6. Test for voltage drop across ground circuits, refer to Electrical, Wiring Diagram Information.
HEADLAMP BULBS BURN OUT FREQUENTLY 1. Integrated Control Module (ICM) not controlling voltage. 1. Test and repair Integrated Control Module.
2. Loose or corroded terminals or splices in circuit. 2. Inspect and repair all connectors and splices. Refer to Electrical, Wiring Information.
HEADLAMPS ARE DIM WITH ENGINE RUNNING ABOVE IDLE 1. Charging system output too low. 1. Test and repair charging system, refer to Electrical, Wiring Information.
2. Poor lighting circuit ground. 2. Test for voltage drop across ground circuits, refer to Electrical, Wiring Information.
3. High resistance in headlamp circuit. 3. Test amperage draw of headlamp circuit.
HEADLAMPS FLASH RANDOMLY 1. Poor lighting circuit ground. 1. Test for voltage drop across ground locations, refer to Electrical, Wiring Information.
2. Variable 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 Electrical, Wiring Information.
4. Faulty headlamp switch. 4. Replace headlamp switch.
5. Front Control Module Malfunction. 5. Refer to appropriate ICM/FCM diagnostics.
HEADLAMPS DO NOT ILLUMINATE 1. No voltage to headlamps. 1. Repair open headlamp circuit, refer to Electrical, Wiring Information.
2. No ground at headlamps. 2. Repair circuit ground, refer to Electrical, Wiring Information.
3. Broken connector terminal or wire splice in headlamp circuit. 3. Repair connector terminal or wire splice.
4. Faulty or burned out bulb. 4. Replace headlamp bulb(s).
5. Integrated Control Module malfunction. 5. Refer to appropriate Body Control Module diagnostics.
6. J1850 Bus Communication 6. Verify messages being transmitted by Instrument Cluster and received by FCM.
7. Front Control Module Malfunction. 7. Refer to appropriate ICM/FCM diagnostics.
HEADLAMPS ON WITH IGNITION IN RUN, WITH HEADLAMP SWITCH OFF 1. Faulty headlamp switch. 1. Replace headlamp switch (review Instrument Cluster logged faults).
2. Diagnostic tool indicates (4.7 - 5.0V) on headlamp switch input to Instrument Cluster. 2. Inspect and repair terminals, connectors and open circuits.
3. J1850 Bus Communication. 3. Verify messages being transmitted by Instrument Cluster and received by FCM.
4. Front Control Module Malfunction. 4. Refer to appropriate ICM/FCM diagnostics.

FOG LAMP DIAGNOSIS 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 Electrical, Charging,
4. Battery has insufficient charge. 4. Test battery state-of-charge. Refer to Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Electrical, Battery System.
6. Poor lighting circuit ground. 6. Test for voltage drop across ground locations. Refer to Electrical, Wiring Information.
FOG LAMP BULBS BURN OUT FREQUENTLY 1. Charging system output too high. 1. Test and repair charging system. Refer to Electrical, Charging.
2. Loose or corroded terminals or splices in circuit. 2. Inspect and repair all connectors and splices. Refer to Electrical, Wiring Information.
FOG LAMPS ARE DIM WITH ENGINE RUNNING ABOVE IDLE 1. Charging system output too low. 1. Test and repair charging system. Refer to Electrical, Charging.
2. Poor lighting circuit ground. 2. Test for voltage drop across ground locations. Refer to Electrical, Wiring Information.
3. High resistance in fog lamp circuit. 3. Test amperage draw of fog lamp circuit.
FOG LAMPS FLASH RANDOMLY 1. Poor lighting circuit ground. 1. Test for voltage drop across ground locations. Refer to Electrical, Wiring Information.
2. Variable resistance in fog lamp circuit. 2. Test amperage draw of fog lamp circuit.
3. Faulty fog lamp switch (part of headlamp switch). 3. Replace headlamp switch.
4. Loose or corroded terminals or splices in circuit. 4. Inspect and repair all connectors and splices. Refer to Electrical, Wiring Information.
5. Is relay engaging properly? 5. Verify function of fog lamp relay in IPM.
6. J1850 Bus Communication. 6. Verify J1850 message (fog lamp info) transmitted from Instrument Cluster and received by FCM.
FOG LAMPS DO NOT ILLUMINATE 1. Blown fuse for fog lamp. 1. Replace fuse. Refer to Electrical, Wiring Information.
2. No ground at fog lamps. 2. Repair circuit ground. Refer to Electrical, Wiring Information.
3. Faulty fog lamp switch (part of headlamp switch). 3. Replace headlamp switch.
4. Broken connector terminal or wire splice in fog lamp circuit. 4. Repair connector terminal or wire splice.
5. Faulty or burned out bulb. 5. Replace bulb.
6. Is relay engaging? 6. Verify function of fog lamp relay in IPM.
7. J1850 Bus Communication. 7. Verify J1850 message (fog lamp info) transmitted from Instrument Cluster and received by FCM.

DAYTIME RUNNING LAMP (CANADA ONLY) DIAGNOSIS CONDITION POSSIBLE CAUSES CORRECTION
DAYTIME RUNNING LAMPS DO NOT OPERATE 1. Parking brake engaged. 1. Disengage parking brake.
2. Parking brake circuit shorted to ground. 2. Check cluster telltale, refer to the appropriate wiring information.
3. Headlamp circuit shorted to ground. 3. Refer to the appropriate wiring information.
4. FCM, Instrument Cluster not programed with Canadian country code. 4. Check country code.

So there are a couple of possibilities for your vehicle. I would first try a headlight switch then if that doesn't fix it, try and get a OBD diag computer on it to see if you have any codes in the FCM. If so, that could get costly to fix. Basically, if it isn't the headlight switch, you're going to have to fork over some money.

Beohbebewhy

I don't have any of the test equipment to test the FCM, BCM or the ICM, so I am just going to take it to a diagnostic shop and get them to fix it. I'll post the resolution as soon as I get it diagnosed in case someone else has the same problem. Thanks a lot.

Bill Liddell

Hmmm. None of these quite fits my problem. My 97 Dakota, the headlights come on and run for a variable time under an hour and then shut off.

mack1

Hi Bill and welcome to TSF,

Here's a thought. Several years ago, my brother-in-law had a similar problem with a Ford car. In his case, there was a thermal breaker in the headlamp circuit that had become weak. (normal current would cause it to overheat and open the circuit untill it cooled down, then reset itself) The idea behind the thermal breaker instead of a fuse was to try to keep head lights working even through intermentant shorts. If your Dodge has a similar breaker, I would suspect it.

Otherwise, I would look for a loose wire or bad ground circuit.

If you have electrical prints and would like to post them here, I would be glad to help you track down the problem. If you need guidance on posting prints here, I can help.

Very best regards,
Mack1

diccar

Hi Thread:

Any word on the fix for the above. My problem is identical

richie-60@hotmail.com