taillight help!

[epthree04]

i have a 70 c/10 and everytime i hit the brakes it will blow the fuse. i must have a short somewhere but im having a hard time finding it. also if i turn my lights on the headlights come on but not the tails but i can turn on the blinkers and the tails work fine. anyone have any suggestions? thanks!

[cdowns]

first place i'd check would be the wire harness running down the driver side frame rail especially where the clips are that hold it in position while you're under the truck also check to see that you have a goosd clean ground from the box to the crossmember

[Longhorn Man]

actually, most damage is found under the rear bumper, where the trailer harnesses have been spliced in over and over through the years.
If that checks out OK, check the harness from front to back (or back to front...either way) and look for a wire crushed, chafed, kinked or what ever.


*edit*
After rereading that, I'm thinking it'll actually be in the turn signal switch or in the steering column. Were you just working in there recently?
Reason I say that;
The fuse blows when you hit the brakes, not when you turn on the parking lights (all on the same fuse, allong with the dome light and the dash lights) This means the problem will be in the circuit for the brake lights, not the dash, dome, nor parking light circuit.
The brake light get power from the turn signal wires... one green, one yellow. (which, oddly enough, are powered from another fuse)
If you can send power down each wire, the yellow, and the green (with the turn signal being turned on in one and the other position) without blowing a fuse, then you know those wires are OK.
The brake light signal goes from the fuse box, to the brake light switch then up to the turn signal switch, where it is then devided into the green and yellow wires...which we already determined was OK.
Check out the brake light switch, if no external damage is found, unplug it, and (with a new fuse in place) place a jumper wire from one terminal to the other with a small piece of wire.
If the brake lights light up, and the fuse doesn't blow, replace the switch.
If the fuse DOES still blow, then I would inspect the exposed wires to the turn signal, maybe pull the steering wheel and inspect the wires up there on the switch. Then I would grab another switch and just plug it in without installing it, and then see if it works.

[epthree04]

okay i have been working on the turn signal switch. bc the signals didnt work when i got the truck. i replaced it with a new one that my buddy had and then the signals worked but the brake lights and taillights didnt. i tried hooking up the old signal switch but it still didnt work. i will try that trick with the jumper wire on the brake light switch tommarow bc my truck is in for exhaust work today. ill let you guys know if i have problems after that.

[Longhorn Man]

If you dropped the column to do the signal switch, you may have pinched a wire when reinstalling it. I think it's the white wire maybe?

[epthree04]

i dont think thats the problem bc i hooked up the old signal switch,