Hey All,
I've got a problem with my electrical. It started out as a bad left turn/brake light. I didn't have time to change it, and now the other day it just starts working fine again. So yesterday I'm driving and all of a sudden I notice my radio going out when I hold the brake. Not only that but when I press the brake I can hear the top left relay in the fuse box click on the passenger side floor. If I put my left turn signal on, my radio flashes along with the clicking. I brought it to the Ford dealer and they basicall told me they'll need to rip the harness apart peice by piece. So I brought the truck to a friend of mine who's a Subaru mechanic and we swapped the relay's around and it helped a bit. So I went and bought a new relay and now it doesn't click half as loud when I hit the brake, but the radio still blinks with the flasher. Thanks for any suggestions you guys might have!

Josh

 

I assume this is on the '04 F150 in your profile?

Is all your equip. stock and/or have you spliced/added anything?

 

This is a must. Anything electrical that you may have added afterwards might be a fault. I would start here first definitely if it applies to you.

With that said...I would go directly to the Turn SIgnal/Brake Light. What sounds like is happening is that you have a ground somewhere in that circuit. Might be as easy as a loose connection ...might be as hard as a nicked wire somewhere under the seat.

I would definitely start at the area of which you first noticed a problem, that being the turn signal/Brake light. Remove the Bulb and check the harness for any discoloration, Burnt areas, etc. Inspect the wires for the same. Make sure the plug socket is clean and dry (Some ELectra Clean or contact cleaner from your local hardware or Auto parts store will do the trick...Ya dont need alot...just a bit). After the bulb is removed turn everything on again and see if you have the dimming. It might have just been the bulb itself or a poor connection. You might even try replacing the bulb just for the hell of it.

The thing is that Light stopped working for a reason. The Problem is figuring out why? If the above doesn't work then I would try to get your hands on the wiring diagram for the Brake Lights I would look at that and then start troubleshooting. By disconnecting the wire directly leading to that effected light you can isolate that from the circuit. Then try everything again.

THis can take anywhere from 5 mins to days to find the problem. SOmetimes it can be dumb luck just finding the problem. You could have a burned up wire in a wire bundle that you will never see causding you the problem. It is a pain in the butt. Butt with that being said...If your truck is still under warranty I would take it back to the dealer and then nicely explain to them Them That you will appreciate all the time they will take in finding out this problem. Good Luck.

 

Hey thanks for the replies guys. I figured it out. First I replaced the relay and the clicking stopped almost completely.(The parts guys told me there was a problem with the stock relays and my replacement was a different model/color. So now I've just had a slight click BUT the radio still flashes and dimms when I use the brakes. I checked the rear taillight and everything seemed fine. I changed the bulbs for the hell of it and all my problems went away. I couldn't believe that a burnt taillight could produce all these problems. Thanks god I didn't let Ford take a crack at it. They wanted to start by replacing my radio and working their way down the harness. This sure is a nice truck but I've had nothing but problems with Ford service. Thanks again guys!