The drivers side tail light isn't working on 1990 4Runner. Took it out to replace - bulb looks fine. Tried replacing with known working bulbs - no luck. The wiring etc all looks really good. And, the bulbs are making good connection. Everything looks clean etc. Tail light fuse is ok as well. Any ideas what I might check?

 

Have you checked with a multimeter if you are getting voltage to the socket when the lights are on??

I have seen sockets get corroded that you can`t see by looking at them cause this problem.

If this has the trailer light converter they sometimes good bad inside.

Look for pinched, cut , and wires damaged in any way

 

my housings came so corroded the wires were breaking off.
resoldered a new harness on and it works great now

 

I would say the wiring but you said they were ok so that's wierd.

 

One bulb or all 3? Check the ground connection there near the light and also check that the connection inside the socket body is OK. You can't just look at it, you need a meter or test light to check that you are getting a good connection for power and ground. And any chance you have a trailer light wiring harness installed?