I have an 87 F150. I noticed over the weekend that my right brake light wasnt working. The flasher doesnt work on that side either.

I replaced the bulb and checked the wiring at the socket. The tail light does work. I layed the socket with bulb installed in it on the bed where I could see it when I pressed the brake pedal. The brake light started to go on and off when pressing the brake pedal but was much dimmer than the left side. Then all of a sudden it stopped working. I went inside to eat some lunch, came back out and pressed the brake pedal. The right side bulb flashed on and off immediately and not again. It seems to do that every hour or so.

I called Auto Zone and they said to replace the flasher which I did and nothing changed.

Any ideas?

 

Try cleaning the socket,its probably corrision in the socket or connection to it.Sometimes they will short out if they get that way.

 

Sounds like the ground circuit to me. The bulb socket will have 2 contacts inside of it, one is the turn, and one is the brake, the ground is the outside brass socket. Turn on that side turn signal, and depress the brake pedal, (usually a long screwdriver and sliding the seat forward works). Carefully clamp a 12 volt test light around the socket and separately touch the two contacts inside the socket. One should be constant power and the other should flash. If you have nothing on either one, now re-clamp the test light ground to a good ground on the truck and if you now have power the ground leaving the socket is the problem.

Sorry for being so wordy its easy to do, but hard to explain!

Good Luck!