The driver's side brakelight on my 87 PU doesn't work. The bulb is good and I cleaned all the contacts. What's next?

 

Do you have a trailer wiring kit installed? The black box can go bad and cause problems.


Ground wire, etc. all good?

 

Broken wire some place.

Look for damage where the harness splits in the back of the truck.

 

Get a test light and a meter.
Put the black wire on a good ground and check for power
With the bulb removed put the other lead on one of the contacts in the bulb housing (someone or somwthing mashing the brake pedal)