Question about 2006 Dodge Ram 3500 Truck
I have an intermittant problem with my head lights. My lights will go off and on while driving. I commute 55 miles to work and it may happen once, twice, or a dozen times before I get to work. Sometimes it don't happen at all. One time they wouldn't turn on in the morning. When I pushed my foglight switch the lights came on but went back off. Eventually they stayed on.
I took it to a Dodge dealer and they could not duplicate the problem. It is a very stressful situation when the lights go out and it is dark outside.
I stumbled across this thread while seeking a solution for a lighting problem on my 1998 RAM - totally unrelated to this one, as it turns out. But, having read through the posts on this topic, I have a theory which seems plausible, although it seems unlikely that a competent main dealer technician would have overlooked this possibility ....
Many automotive headlamp circuits are protected by thermal breakers rather than fuses - this is intended to prevent sudden total loss of main lighting when the circuit is overloaded - the breaker will normally reconnect as it cools down and the lighting will be restored - and will continue to work if the overload sitiuation no longer exists.
The failing component in this case could be the thermal breaker itself or something in the charging circuit. The reason why this happens only when the engine is running may be because the system voltage will be higher when the alternator is charging the battery and the current flow through the headlamp circuit will be proportionately higher. This additional current could be sufficient to trip a faulty thermal breaker. Alternatively, a fault in the charging circuit may allow the supply voltage to rise over the acceptable limit (around 14v) to a sufficient level where the current draw through the headlamp circuit exceeds the safety limit built into the thermal breaker.
It may be significant that both vehicles mentioned are diesels - presumably with twin batteries. There may be a clue here ..... one faulty battery could cause excessive charging voltage.
Look out for abnormally high voltage indications (if your truck is equipped with a voltmeter) or check the voltage across each battery with a multimeter with the motor running. Check under normal conditions and then with everything you can think of switched on - especially heated seats, mirrors etc - run the heater blower at full speed ... the voltage should never exceed 14.5V. Do the headlamps get brighter as you increase engine revs ? This could indicate a voltage control problem.
Hope this is helpful.
Posted on Nov 19, 2008
Hello again Larry,
Thanks for the excellent response. That makes it so much easier for us to provide assistance.
Even though you went to the dealership, I checked for any recalls related to this problem and there were none. I've been doing some research to find similar problems (and hopefully the inexpensive fix that goes with them). I'm still searching, but I did find a combination of features that causes this type of problem.
Do you have an HID headlight system? Daytime Running Lights?
The two together on Dodge RAMs have had problems where they blink out for no apparent reason.
One other symptom they exhibit is that they work fine with the engine off. It only happens while the vehicle is running. This made me wonder if the dealership tested your vehicle with the engine running or not.
This doesn't 'feel' right, just letting you know what I found.
I agree with you about checking the relays. Under your hood there is another fusebox that houses larger system fuses, relays and breakers. There should be a legend on the cover for which one is which.
Find and replace the headlight relay.
If it was an easy problem to duplicate, I'd have you feel the relay after it happened to check it for heat. The reasoning is that while the relay may be faulty and the cause of the lights going off (like if it was getting too hot), it may also be the most visible symptom of the problem (like something else turning the relay off).
Replacing it is an easy and inexpensive way to either solve or rule out one of the possible causes.
Let me know how it goes, In the meantime, I'll keep looking for other possibilities.
Posted on Oct 05, 2008
I purchased a new TIPM (totally integrated power module) and installed it yesterday. It was not cheap. Ouch! Hopefully it will solve the problem. Driving your vehicle at 70 MPH at night and having your headlights go out, even for just a few seconds at a time, is not FUN.
Posted on Oct 12, 2008
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Posted on Jan 02, 2017
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