Topic: Brake light issues

[mountain,man1]

I was just informed by a state trooper of a brake light issue I'm having on my way home. When my headlighs are off both my brake lights work fine but when I have my headlights on my drivers side brake light comes on for a second then stops working. At first I thought it was a bad bulb I changed it in front of the trooper but didn't fix the problem. So now I figure its in the wiring I believe it may be a bad ground I obviously have power to the light. Any ideas where I should start when I finally get around to it

[gnob]

It could be the other bulb. It could still be a dirty socket. 

[mountain,man1 [OP]]

The other ball was just recently replaced I had to replace the whole fixture on the passenger side rear it broke when I got up against the tree off roading and all those bulbs are new but it is a junkyard fixture

[mountain,man1 [OP]]

do you have a trailer light converter installed for towing? when they go bad, weird things can happen. when your headlights are on, so are your running/parking lights which share harness wiring with brake, turn and reverse bulbs

I have a 1 1/4 inch receiver hitch. I'm pretty sure I do not have a trailer wiring harness I didn't see one the only time I've ever towed with my 4Runner. Depending on how my work schedule looks at the end of the week I may pull the truck in the shop bust out my voltage meter and track it all down. Thank you guys for the ideas

[mountain,man1 [OP]]

 Thank you everybody for the tips. I fixed my brake lights. I pulled both fixtures and sprayed all the sockets and connectors with CRC QD electronic cleaner and replaced both brake light tail light bulbs. Everything is working splendidly now thanks again