ok ive got a 77 302 . the wiring is all screwed up the brake lights dont work, yes the switch is good. the back grounds and bulbs are good too. and no matter witch blinker you turn on both sides blink front and back.

please help
thanks alot

 

Most likely you have a bunch of cut up wires in the back where someone wired in a trailer plug. You would have to have two wires touching each other for them to both come on at the same time like that. Check for frayed wires or taped up areas. Undue the tape and take the stuff apart and redo each light one at a time.

 

If you think the wiring is wrong, here's a diagram to help out.

http://www.autozone.com/images/cds/g...3d800ce985.gif

Look at the right part of the diagram for the rear light wiring.

If you get the wiring straight, and the blinkers and the brake lights still don't work, you may have a problem with the turnsignal switch.