TrkEnvy

So to all the elec gurus, I have a question. I have running lights but no brake lights. I replaced the stoplight switch on the pedal that I thought was bad. Still no brake lights. Where do I go from here cuz its my DD and I need brake lights.

rrgrassi

Checked the fuse?

torquefan

1) Make sure you have power to the brake light switch.
2) If you do, you can jump out the brake light switch with a wire to see if they will come on.
3) After the switch, the brake light circuit goes up the steering column to the signal light switch. That's the next place to go to check the circuit. A diagram of the circuit would be very helpful in checking the path from one end to the other.

Ignore the running lights because they don't really share anything with the brake lights. Do the signal lights and hazard lights work properly?

TrkEnvy

I checked the fuse and it was blown.. So I replaced it with the identical 20 A fuse. Still nothing. The signals work fine. Didn't check the hazards.
I'm gonna check if I have power to the brake light switch tomorrow..

j_martin

Does your key in and headlamp buzzer work?
Yes = fuse OK
NO = fuse blown again.

The path goes from fuse to brake light switch to hazard flasher switch to turn signal switch, where it is steered to the brake lamps that are not being used for turn signal.

Between the brake light switch and the hazard flasher switch, the circuit can be molested by the antilock brake module.

Without diagrams yer up a creek. With diagrams, good luck to ya.

j_martin

There's your problem. Why did you replace a 20 amp blown fuse with a 20 amp blown fuse?

TrkEnvy

Lol.. Thanks I needed that.. This thing has me frustrated. I hate electrical. So I have no power to the brake switch. Ideas??

TrkEnvy

It keeps blowing the fuse.. Could it be my voltage regulator gone bad and letting too much voltage by?? I really need to figure this out.. Driving with no taillights is dangerous.

j_martin

Read my previous post. That fuse powers several circuits, and you have to use the diagrams and a meter to check them out. Some of the circuits aren't even related to brakes. (The old time Dodge way. Used to be that if a kid overloaded the cigar lighter, your ABS brakes failed.)

If you're not up to that, you need help.

TrkEnvy

My truck is a 91.5.. Would I be able to use the diagrams in the sticky?

j_martin

Should be real close.

torquefan

Does it blow the fuse instantly when you touch the brake pedal, or just periodically when you are driving? If you can make it blow the fuse by stepping on the brake while the truck isn't running, you have eliminated the charging system as a suspect.

Other than that, have a good look at any trailer wiring somebody may have added. It's a common place for trouble.

TrkEnvy

No the fuse is fine when the truck is off and the brake lights work.. But when I drive it the fuse blows and I can smell it.. wiring is not my forte. I may end up having to take it somewhere..

TrkEnvy

Lost turn signals too tonight.. Still have hazards though..

torquefan

If the signal lights blow a fuse too, it proves that the fault is downstream of the signal light switch, and the fault isn't specific to the brake light circuit. That's not a bad thing, it gives you a direction to go in.

First, open the hood and look at the outside of the big bulkhead connector on the driver side of the firewall. You should see a smaller harness break out of it and go down toward the driver side frame rail. That's the harness that goes to the back of the truck to power the rear lights. I remember seeing one years ago that chafed on the lip of the bottom of the firewall, before it got to the frame rail, have a good look at it there.

From there, just follow that harness to the rear of the truck and look for any chafing and bare wires. Most of these problems are right at the back of the truck, where you have wires that have been blasted by gravel kicked up by the rear tires, and also lots of extra wiring added by people for trailers. Wiring in the steering column is also a possibility too.