No brake light or tail lights

[Nate781]

I need some help please. I have been working on a 1970 C10, I've replaced mostly all of the wiring harness on the truck. Expect for the Engine harness and turnsignal switch. I have no brake lights or tail lights. All ground straps are correct for that truck, ive added some extra ones thinking it was a ground. Im thinking it could be turnsignal switch. I know that the main wire completes the loop of the tailights but Im running out of ideas.

[El Dorado Jim]

post this in the electrical section and you will get an answer.

[kwmech]

Did ya make sure the connection did not come loose at the firewall?

[Andy4639]

There is a round connection at the rear of the truck on the drivers side frame rail. Take it a part and take a test light and see if you have any power to it. Have some one push the brake pedal down and turn the lights on and check it. If so take the rear housings a part and clean the screw connections. They ground the housing to the truck. Check the connections in the housing also.
All wiring run through the turn signal wires.

[Nate781]

Originally Posted by Andy4639

There is a round connection at the rear of the truck on the drivers side frame rail. Take it a part and take a test light and see if you have any power to it. Have some one push the brake pedal down and turn the lights on and check it. If so take the rear housings a part and clean the screw connections. They ground the housing to the truck. Check the connections in the housing also.
All wiring run through the turn signal wires.

I replaced the rear taillight wiring harness and made sure all rear grounds were grounded to bare metal. The last time I had a test light on the rear harness and didnt get power to the back. I still think its up front somewhere.

[Nate781]

Originally Posted by kwmech

Did ya make sure the connection did not come loose at the firewall?

Well, thats what I checked the last time and the the brake lights and tailights worked. I checked the bulkhead and made sure everything was still ok and no wires were lose. Its a brand new under dash harness and bulkhead. Tightened it up and lights worked now Im back to square one with no lights or brake lights. hahaha

[Andy4639]

Originally Posted by Nate781

I replaced the rear taillight wiring harness and made sure all rear grounds were grounded to bare metal. The last time I had a test light on the rear harness and didnt get power to the back. I still think its up front somewhere.

Follow the wiring back toward the front until you find power.

[Nate781]

Originally Posted by Andy4639

Follow the wiring back toward the front until you find power.

You said all the wires go through the turn signal switch. Im still thinking its a wiring issue up front. Turn signal switch is all I can think, since a I replaced almost every harness. Im not getting any power to the front part of the rear harness, Im talking about the harness plug that plugs into the fire wall right by the gas pedal. I wont get any power to the orange wire that plugs into the brake switch. Its a pain thats for sure

[Andy4639]

Originally Posted by Nate781

You said all the wires go through the turn signal switch. Im still thinking its a wiring issue up front. Turn signal switch is all I can think, since a I replaced almost every harness. Im not getting any power to the front part of the rear harness, Im talking about the harness plug that plugs into the fire wall right by the gas pedal. I wont get any power to the orange wire that plugs into the brake switch. Its a pain thats for sure

Per this drawing. Check white wire coming from turn signal switch to stop light. See if the white wire has power.