Tail light trouble

So got this trouble with my left side tail light.. when I step on the brake the left turn signal indicator in the dash lights up.. not bright but you can see it. If I step on the brake when using the left turn signal it flashS fast, let off the brake it goes back to normal .. all the lights work.. any ideas where I should start looking for the trouble??

 

Do you have a trailer wiring harness on your truck? If so it could be that causing the problem. If not then sounds like a bad ground to me.

 

@mechanicjon
@BartMaster1234

 

Yes it has trailer wiring, but have unplugged it thinking that was what was causing it. Still doing it after

 

I had this issue, eneded up being moisture in my fuse box inside the cab. It was also causing my reverse lights to illuminate dimmly.

 

Have you replaced any bulbs recently? Check bulbs for good connection. When you unplugged trailer harness did all the connections look clean and none were burnt? It sounds like a ground problem. Use a volt meter and check ground continuity from light socket to frame.

Not a good place to have moisture.

 

No it's no.

It was getting water in the box from a bad sun roof drain, all sunroof's are a controlled leak, and it's only a matter of time before it's uncontrolled.

It was that experience why I will never own another vehicle with a sunroof.

 

Sounds like a short to power or a short to ground. One of the wires responsible for the brake light might be rubbing against the wire for the turn signal. Hell one of the copper traces on the instrument cluster might be arched.

I'd say check for damage to any wiring but it could be something else.

 

see if this helps

 

Thanks for all the help.. I'll dig it to tomorrow and see what I can find..

Plugs looked good.. trailer hitch and wiring are only 2 month old