A while back I replaced my left tail light assembley with a used one of those notorious aftermarket non-OEM pieces of melting crap that pretty much keeps the tail and brake light from ever working. So at night I just flip on the fog lamps and leave the brake lights to the other two. But when I have the brights on, the fog lamps go out and I believe the brake lights are also inactivated. Not not good at all.

What the devil is the problem here? Fuses check out. I'm guessing it has everything to do with that darn tail light. The interior wiring harness was replaced six or seven years ago, and it reaches all the way to the back. The car leaks rainwater like a rusty bucket though, and the cargo spaces behind the wheel wells do collect a lot of moisture. What should I look for in checking these circuits?

As always, your advice is greatly appreciated. Thanks!!