The brake lights work, just one is brighter than the other.
When I turn on the headlights they both light up fine. But normally they aren't they same. What the hell....
Well, the "Brake" lights should not come on with the headlights, the rear parking or running lights should be on. Need to know what year the car is. THe brake lights are dual filiment bulbs.
On to the problem. A dim light is most likely a bad ground, a corroded contact on bulb socket and/or the bulb itsself.
ALso, if someone has done any modificartions to the wires in the trunk, it's possible that the wire of the brake light and the parking light got switched on one bulb, and you are lighting a parkng light filiment on one side and a brake light filiment on the other side-one is brighter than the other inside the same bulb...
I'm betting that you have a wiring problem. Most likely a bad ground. I know wiring problems can be a pain to figure out, but you already have it down to one circuit and you know exactly where to start looking. Do some continuity testing with a multimeter and you'll know pretty quick what's going on.