1970 pickup fuse blows when brakes and?
 

Need some help to figure out where to check first
when headlights are on and press brakes I get a short...
the brake light works good if the headlights are off and vise versa
any ideas? I know they share the same fuse...thanks

Re: 1970 pickup fuse blows when brakes and?
 

Just a thought...

Since the taillights are on with the headlights and the taillight and brake light filaments are in the same bulb, you may want to try removing one bulb at a time, turn on the lights and hit the brakes to see what happens.

Re: 1970 pickup fuse blows when brakes and?
 

Good idea..thanks

Re: 1970 pickup fuse blows when brakes and?
 

Hey I'm having the same issue, what did you do to fix it?thanks

Re: 1970 pickup fuse blows when brakes and?
 

I had a mid 80's truck with a similar problem. I'm not sure if it was factory or not but the sockets were full of grease. I assume it was dielectric grease, but it was all dried out and was causing high resistance. It wasn't enough to blow the fuse if the headlights were of but with everything on it would blow the fuse as soon as I touched the brake pedal.

Re: 1970 pickup fuse blows when brakes and?
 

I just recently went through similar troubles and after about a dozen blown fuses I got it figured out but for me it was very complicated.

It started RIGHT after I finally replaced the broken front right turn light socket so I assumed it was the cause.

Long story made short ( no pun!) it turned out to be a wire chaffing against the rear bumper.But it would only blow a fuse occasionally and thus caused me to scratch my head bald, especially since I have trailer wiring plus camper wiring plus some sort of custom work the original owner did.

46 years of chaffing and it shorted out. I guess they don't make anything to last any more.

I would check the entire system inch by inch.

Re: 1970 pickup fuse blows when brakes and?
 

Will it work fine up till you press the brake pedal is what I understand you are saying. So that tells me it's some place between the brake switch and the rear of the truck.
As stated take one rear bulb out and see if it blows the fuse. If not put it back in and take the other side out and try it. If one are the other blows the fuse then look on that side of the wiring.:chevy:

Re: 1970 pickup fuse blows when brakes and?
 

I had the problem on my 1970 C20. What I did was replace the wiring to the rear lights. There are two wires from the dash to the back.

Re: 1970 pickup fuse blows when brakes and?
 

I replaced the headlight switch and that's it..it worked

Re: 1970 pickup fuse blows when brakes and?
 

Headlight switch

Re: 1970 pickup fuse blows when brakes and?
 

Thanks guys! Started going threw some wiring and found my hi/low switch on the floor was completely melted to the floor. Haven't had a chance to check the fuse yet. I checked the dome light wires they all look good. Po had changed the headlight switch. I still need to check the harness and so on.

First c10
1969 shortbox
454/t400/12 bolt