I keep having my brake light fuse blow. It doesn't blow as soon as I hit the brakes. In fact it will last a day or so and then it will blow...not right away.

I have replaced both bulbs and the brake light switch.

I'm lost and I'm terrible with electrical. Thank u in advance

 

On the older models, it was the same fuse as the dash lights. Perhaps you're grounding out up there somewhere. Any water in the tail lights?

 

Sorry I should've said year. 1991. And no water visible in tail lights and my dash lights work perfectly fine

 

No worries. It was my 86 that had dash and tail lights tied. Wasn't sure about newer

 

Does anybody have a wiring diagram for the brake lights? 1991

 

You have a brake controller? Might try unhooking it. had this issue in my 79

 

I do not have a brake controller

 

The newer trucks, and almost all modern vehicles, have the dash and taillights tied, since they're both on the parking light circuit of the headlight switch. They're not connected in any way (except for the ground) with the brake lights. The brake lights do go through the turn signal switch, however, so that MIGHT be a suspect.

 

I just replaced the turn signal switch. May have to double check it. I find it odd how the brake lights will work for a while and then just pop. Going to go out and look for loose wiring or bad ground etc in a little while. Wish me luck.

 

remove and inspect you tow wiring and plug. this is a comin place to find shoty wiring. look for worn thru plastic.

 

Would this be the gray harness with the cap on it? Sorry dumb question I know lol

 

Ok so the solution to my problem was the turn signal switch itself. I had replaced it and I guess it was rubbing on the steering wheel itself causing a lead to short out. I made sure it was tucked in nicely when I replaced it again. Haven't had a problem for a while now!

 

Thats good to hear, and thanks for coming back to post the solution for others to know!

 

lifesaver! Im having this issue on a 73 F100 and the turn signal switch was bad too . Thanks!

 

I changed the brake signal switch out, probably didn't even need to, because it is blowing a fuse every now and then. Everything seems to be solid in terms of bulbs and switches. I bet it is doing something similar to this post. But finding it will just frustrate the hell out of me.
Paying my mechanic friend to drop a new fuel filter in on Monday. Might just let him mess with it since it seems to be faulty wiring somewhere. Dadgumit.