Dash lights come on when braking

So recently I've had electrical issues in my 01 Taco. This started with my turn signal fuses blowing randomly. I took apart light assemblies and found what maybe was a ground or wiring for a trailer harness before that went under the frame and was bare above my spare tire holder. Every now and then it would touch and short the directional signals and blow a fuse, I turned signals on and touched this wire to frame and fuse would blow. So I thought I had found the problem, cut wire, made sure it didn't contact anything and was fine for a few days. During the work I broke rear passenger tail light assembliy lens and had to grab one from an 03. Everything was great until I realized with my headlights off when I brake my dash running lights come on and radio and other lights dim like if I turned on running lights. Also the brake light stick on when I do have running lights or headlights turned on making the truck currently undrivable at night (they don't stick on when running/headlights are not on). I'm sorry for the long winded message but needed the details in here, if anyone has insights I would so appreciate it, but I wont get my hopes up. I also installed tail lights brush protectors around this time but they don't interfere with wiring, thought id put in all info though. Thanks guys!

 

Sounds like in the wiring harness you got, the running lights are connected to the brake lights, and vice versa. Therefore, when you hit the brakes, it is sending power to the running lights circuit, which includes your dash lights. When you turn on your parking lights (done when turning on headlights), you're turning on the brake lights.

 

You mean the new taillight assembly? I didn't get a new wiring harness just a new passenger taillight assembly. Thanks for the reply btw.

 

Do you have trailer wiring? Usually when I pressure wash my truck, the water short circuits it or something and my parking lights come on when I brake. It goes away after an hour or so when it dries.

 

mice

 

Yeah, the taillight assembly. Someone probably messed up the wiring in it.

 

I would say as a quick test disconnect the new tail light assembly you installed and
try it and see if it still has the problem. Possibly the brake light bulb filament
shorted across the park light filament. Just a thought.

 

YEP, I switched the new lens from newly purchased (but used) taillight assembly to my old assembly and connected it and the problem disappeared. Clearly the wiring in the new assembly is messed up, luckily I only broke the lens on my old assembly, switched then and back to normal.

A big thanks to everyone who replied, I read every answer and considered it what a help this forum is even if this was a common sense issue thanks again!