stop light fuse blowing

[mike1971c10]

morning, Someone please point me in the right direction. I'm now blowing the tail-stop dome fuse. It worked fine two days ago but today it blows the fuse.
a blown fuse usually means a short. It blows the minute I touch the pedal. Where do I look? I just replaced the turn signal switch, would that be something to check?

mike

[big block 72]

Pull the turn signal switch back out, the switch either bad or one of the wires is shorting out on the steering column.

[HIGHWAY BY THE SEA]

Last time that happened to me I had an exposed wire shorting it out.

[mike1971c10]

I just talked to Dave @ American Auto Wire and he told me how to troubleshoot the stoplight part of the turn signal switch. That came out okay and I have turn signals and running lights on the rear. I guess I'll go from the fuse box to the stop switch and see if I can find the short
mike

[VetteVet]

If your fuse blows when you step on the brake pedal then you have a short in the white wire going to the steering column or in the column itself, or in the left and right turn signal wires.

Put in a fresh fuse and unplug the column connector, does the fuse blow? If yes the short is between the stop light switch and the column connector. If no, then the short is in the white wire that goes up into the column.

Use an ohmmeter and check for zero ohms on the white wire in the column connector and the column, or any good ground. You are looking for no reading on the meter.

Be sure that the turn signal lever and the hazard switch is off.

[mike1971c10]

Hey VetteVet, I disconnected the turn signal switch and tried the brake pedal. Nothing happen. So the problem is in the t/s switch? I don't have an ohmmeter

mike

[VetteVet]

The white brake light wire also powers the yellow and dark green wires to the rear of the truck. If one of those wires is shorted to ground then the fuse will blow as well. To isolate the column TS switch unplug the column switch and run a jumper from the white wire on the brake pedal side of the connector to the same wire on the column side of the switch connector. Then step on the brake pedal and see if the fuse blows. If it does then the short is in the column and if not then one of the brake light/turn signal wires is shorted.

A multimeter is a very useful tool and they can be bought for just a few dollars. You can check continuity with a test light too, not as good as a MM but still better than blowing fuses and guessing.

[Doug's68SS]

long shot but this happened to me on my 68 started blowing fuse when brakes applied but only when moving. setting parked it did not blow. turns out my battery tie down was loose and my battey was bumping the rear of the right front turn/park light when stoping (even at slow speed in drive way)and was blowing the fuse.