I'm new to this forum and am hoping some knowledgable folks can shed some light on my truck's problem. I have a 2004 F150 Screw. It's been a great truck, but recently the electrical has been acting up. The interior lights as well as the cargo light flashes at random. Very random and not all the time. It can happen while driving down the road and/or can happen while the truck is parked with keys out of ignition. Lights may turn on for a fraction of a second before going off, or may stay on for a few seconds before turning off. Only way to prevent this from happening that I've found is to dial down the toggle switch until in the off position. However, doing this prevents me from having interior lights at night when needed. Door ajar light is not on, so I don't think the door ajar sensors are the issue. Can anyone tell me why this is happening and how to resolve the problem? Very frustrating and don't want to drain my battery. Thanks for any and all feedback.

 

My bet is you have a broken wire leading to one of the door switches, and it occasionally finds a ground. The same wire could also be pinched somewhere having the same cause/effect.

Andy

 

More likely the dimmer switch is going bad.

 

Thanks OhioLariat and glc. I will start with replacing the dimmer switch. Should be a simple procedure. I will post on here once it's replaced and I can tell if it fixed the problem. Appreciate your help!

 

Is there a way to test the dimmer switch with volt/ohm reader to see if it's going bad?

 

I had this exact issue - turned out the bulbs had bad connections. Went ahead and replaced the bulbs - was the last thing I thought it would be, but figured what the heck...havent had an issue since - been about a month.

 

Thanks rbarwic1. Strange that all bulbs needed replaced. Did you replace the bulb for the cargo light too?

 

Yeah, all of mine were burnt out (or slightly charred). I did have the lights pop on and off for a second a few days back, so it doesnt appear this fully fixed the issue. Might have just been adding to it. I have the brake light that pops on and off randomly, so I think it might be tied back to a cluster issue. I plan on pulling the cluster and retouching up all of the solder points in the near future to see if this fixes the issue.

Something to note, when the light did come on there was a slight popping noise behind the radio (seemed like it anyway) but it was only once, and I wasnt expecting it, so it very well might not be actual location.

 

I recently had a problem with my interior lights flashing on and off when the drivers door was open. In my case, the problem was a broken ground wire in the wire loom running through the door boot. If that is your problem, you have to remove the door panel, disconnect the boot from the wiring loom (inside the door!!) and then pull the boot through into the door so that you can access the wiring. It's doable, but a real PITA.