So the story starts a couple weeks ago when a mechanic I happened to drive by let me know my brake light wasn't working, I replaced it and the brake light works. I didnt check for tail light operation then. So next I notice the taillight(left side only) doesn't work, I inspect the bulb and socket, looks good. I bent the contacts on the bulb down and wiggled it around in the socket, by doing this I was able to get the brake light to come on, when the running lights were on, on the right side the tail light glowed steady. Why would the brake light be receiving power?

 

i would say check all your grounds, make sure they are all tight and metal to metal otherwise i dont know what to tell you

 

Which vehicle are we diagnosing here? A 4Runner? Include your vehicle within your signature so more people can help out here.

Brake/tail lights are a dual filament bulb. So one can work and the other not-because one of the 2 filaments is burnt out or grounding to the other. Have extra bulbs available and see if any of the symptoms changes.

I'm confused how you could bend the contacts of the bulb.

4 pin hitch/Towing connector out back? A common "black box" failure.

Give us a little more to go on and I am sure we can help talk this out .

 

Thats weird that my signature isnt showing up, must be because I'm on my iPhone. 2000 4runner limited with tow package. Any way to test this black box you speak of? I have tried several different bulbs.

 

I confirmed that the tail light wire isn't getting power with the running lights on

 

try a 4 pin tester at the rear hitch connection-they run about $5-8 at an auto parts store or Harbor Freight locations