1970 C10 No Brake Lights or Tail Lights

[Nate781]

Ive been working on a friends 70 short bed. I replaced all of the wiring harness's on the truck. He did not have tail lights, brake lights and back up lights. I noticed a majority of his wiring had been cut or shorted out. So I replaced all of the harnesses, light switch, dimmer switch except the engine harness and turn signal switch. Still have issues. I replaced the brake switch under dash thats by the brake pedal. I got the the lights working last month when I unplugged the bulkhead harness and re tightened the bulkhead. Now no lights again. Ive made sure all grounds are grounded correctly and added a couple more. NOT sure whats going on. Im thinking its in the turn signal Any help or suggestions would be great.