My passenger side headlight (Low Beam) goes on and off intermittently. Usually when it goes out, it only stays out for a day or two and then comes back on. This time it's been about two weeks. All other lights work. I checked for voltage and it is reading 12v both on high and low beam but the light still does not come on. The 30 amp fuses on both sides in the fuse panel are good and both have power. I even switched them to see if that would make a difference. This has been going on for over three years btw. A mechanic said it might be the little silver computer box on the side of the fuse box. He said he thinks it might have a relay in there that is going bad??? My truck is an '04 Cummins QC. Any ideas?

 

Hi,

Does the computer detect the lamp failure?

I do have an electronic copy of the 2004 Ram service manual. I looked it over a bit and it looks like the system has relays in the Front Control Module is the primary system control.

I have tried to attach a pdf of the 3 pages of diagnostics for the right headlamp.

jim

 

The computer does say I have a lamp out. I checked on the underside of the cover for the fcm and I didn't see a relay specifically for the head lights. I'll look over the pdf, thanks btw, and see if I can find anything that makes sense.

 

I had a guy pass me today pulling a fifthwheel & when he put his left turn signal on his left head light would go out. When he cancled the signal the head light would come back on. He passed me several times on the hills ( i was in my work truck) & it did it every time. I didn't see a cb antenna or I would have tried to reach him. Has any of you guys had that problem?

 

Sounds like he only had DRLs on. My 07.5 does that. Come to think of it I don't know that the headlights don't do the same thing. I think it makes the signal easier to see, since it is so close to the headlight.