trouble with headlights

[DBohl]

A short time ago I noticed that when driving with my low beams on every once and a while my lights would go out for a split second then come back on. This started happening more frequently, mostly when going over bumps but sometimes on smooth roads too. The other night my lights went out and stayed out . I tried to put the high beams on but they would not stay on unless I held the switch in place. I was able to get the fog lights to come on. I turned the headlight switch off and then back on again and my low beams came back on a few minutes later the situation repeated it's self. After I got them to come back on again I left the fog lights on and everything was fine for the rest of my drive. This has not happened enough to know for sure but, (1 ) It seems like the low beams won't go out if the fog lights are on at the same time. (2) when the low beams go out the high beams won't stay on unless held in position. (3) lights going out seems to be more likely to happen when going over bumps in the road (4) this has never happened when driving with the high beams on. I'm planning a long road trip over Christmas so I need to get this figured out. I don't want to be in the mountains of Montana and have my lights going out. I'm going to start buy looking for loose connections and grounds I also wonder if a relay could cause this to happen . Last resort would be tearing into the dash to get at the head light switch. I'm afraid I'll end up recking it with all those hidden fastners and such . I did order a FSM but it won't be here until next week. I need to get going on this cause I'm running out of time. I may have to cancel the vacation if I don't get this figured out soon. Thanks for your help in advance. Doug P. S. the truck I'm having problems with is the 2004

 

[jhenderson]

I had the same problem. Try checking the FCM. It mounts to the fender side of the under hood fuse box with 4 screws. Clean all of the pins and twist each pin EVER SO SLIGHTLY to ensure a good connection. It worked for me.

 

[DBohl]

what is the FCM? I'll give it a try if I can find it ( not sure what I'm looking for ) Anybody else got any ideas ? Thanks, Doug

 

[jhenderson]

front control module. controls lights as well as several other functions. 4 by 6 by1/2'' alum. box. pins enter fuse box directly. no wires.

 

[rjones]

Does that box also control wipers and blower motor?