My rear drivers side turn signal and brake light goes out randomly. I switched the bulbs from the passenger side and it worked for a couple days and now it is out again. So I switched them back and they both work again. The blinker/flasher up front always works, the cab brake light is functioning, and the passenger side has never gone out. Anyone have any ideas what it could be? I checked the fuses and the wiring connectors all look fine. 06 King Ranch

 

sounds like a ground problem........... I don't know if the ground runs thru the wiring harness or there is a ground wire connecterd to the frame/body metal somewhere close to the light socket.

I just changed a tail light bulb on my truck. I was suprised to see a lot of mud/dust/road crap built up on the wires that lead to the light socket. Possibly you have a damaged wire...........

maybe you can reach the wires from the wheel well and wiggle them a little. If the light blinks, I'd be looking for a damaged wire.

Bob the Fool

 

Check the bulb sockets themselves. These newer style double filiment bulbs that are used today remond me of the Christmas lights; they have tiny wire type strands that have to make contact with the copper connectors in the sockets; they don't always do this.

I had a side marker light on the drivers side headlight bucket that would work, flicker, and not work at random times. Bulb checked good (ohm meter). I finally took a small flat bladed screwdriver and bent the brass tabs out slightly to make sure they made good contact with the bulb's tiny wires.

Works great now. I wish they still used the bulbs with the lead "****" on the end...they never gave me any trouble.

 

I'm having this same problem and I tried the suggestion from Bucko to no avail. Switched the bulbs from the passenger side and still have the same problem on the drivers side. I can't locate the ground for this side to see if that's the issue. Anyone know the location of the ground? I have a 2006 F-150 STX.

 

I ended up buying new bulbs and replaced both of them, haven't had any problem since. Don't know if you already tried this but it fixed the problem I was having.

 

new bulds seem to help a lot. I had a problem that seemed similar. the filiment can break at the end and wiggle on and off sometimes, very hard to see too