So, I've replaced the big red relay a year ago for something similar, so I'm a little worried that perhaps some electrical fault is burning out those (very expensive) relays.

When the headlights are off, the taillights are off, and when I hit the brakes the passenger brake light works normally but the driver side brake light is dim as if the taillight has turned on.

When the headlights are on, the taillights look normal (both on but dim), but when I hit the brakes the driver side brake light shuts off.

It's like some sort of wire is switched, or a signal is reversed, but what wire is it? I swapped those quick-disconnect wires around the taillight bulb and then the light was on bright all of the time, which makes sense to me. So the other wire is sending the opposite signal or something?

What should I do, other than swap the red relay again. I feel like it may keep burning out relays :/