Drivers side tail light CONUNDRUM

Here's the facts... Stock 95 Toyota 4Runner. Great shape, and low miles. The blinkers, head lights, running lights, Hazards, etc. All work flawlessly except the Brake lights. The passenger tail light assembly works as it should 100% of the time. While driving at night I have a running light and a brighter light when braking. The drivers side differs slightly, I have a running light, and when braking I get no light. Lights out. Its indicative to the drivers side unit because I bought a new light and it did the same thing. I swapped the proven light on the passenger side to the drivers side and the same thing happened. Light goes completely out when I brake. Checked all fusses and they appeared to be fine, plus all systems and lights work accept when I brake and the brake and running light goes dark on the drivers side.

I'd really appreciate some ideas. Thank you in advance.

DB

 

Sounds like the drivers side light is searching for a ground. Check the ground wires at the sockets and see that they are truly grounded.