Wiring Issues
 

So i got my truck back from the shop yesterday. its a 1994 chevy extended cab stepside. 5.7. I need to know where all the grounds and tail light wires are. MY problem is that all the taillights are plugged in and none of them work. If anyone had a diaghram to help me out it would be greatly appreciated. I just need to know where to start looking. Thank You in Advance.

Re: Wiring Issues
 

Raise the hood and on the lower right side (drivers) there will be a bulk head of wires and i believe the lowest on on the right is the harness for the tail lights. Crawl under the truck and find the loom going to the tails and make sure which connector it is.

Ill start with a simple ? you did check the fuses, right?

Do the dash lights work ok?

Re: Wiring Issues
 

Checked the fuses. All of them are good. Headlights work. Dash lights dont. Horn doesnt. I think i have a ground not hooked up. I was just trying to get some information before my brother came over to help me figure it out. Ill Keep looking. Thanks Guys.

Re: Wiring Issues
 

So theres a little tan/white wire running parallel with the tailight wires from the engine compartment to the back. What is this for?

Re: Wiring Issues
 

Not sure. Are the wires good in the loom to the back?

Re: Wiring Issues
 

no there all pulled out in the back.. i think ineed to start connecting them with new connectors. which one is the ground? The wireing on this truck is so screwed up. It was wrecked three times by po's. Thank you scotts for atleast hearing me out and helping me with this one.

Re: Wiring Issues
 

Hey no problem.

ground "should" be a black one, its been a while since i have messed with car tail lights. Big trucks are different color grounds and messes me up sometimes :lol:

What i would do if it is messed up like you say is go to a local pull-a-part and get that harness off a donor truck and that way you know that it is good and least you wont have to patch it together. Those butt connectors will corrode later especially up North in saltier conditions and the things you fix now will cause you problems later.

Re: Wiring Issues
 

On the early TBI trucks the fuel pump feed wire is light brown with a white stripe (tracer). By 1994 this wire is gray.

Is your truck a mix of parts from other models years?

Re: Wiring Issues
 

Remove the headlight switch and look at the terminals to it to see if the connector is melted.

You might not be able to unplug the headlight switch if it is melted to the connector.

Do the rear turn signals work?

Re: Wiring Issues
 

i did some more digging around. Connected stuff and still nothing... My bed is off a different struck but same year. My fuel pump/sending unit works just fine. I dont know what else to do.

Re: Wiring Issues
 

did you replace the "circuit board" in the tailight housing? those are known for going bad also

Re: Wiring Issues
 

yepp brand new circuit boards and bulbs..

Re: Wiring Issues
 

I'd start at the rear. Test for power to the taillamps. Work your way back to the front from there.

Re: Wiring Issues
 

Ground wire should be black, back by the bumper, but underneath the truck, the ground should connect to the bottom of the bed. I pulled my box to get to the fuel pump and missed that wire, yanked it out without knowing. Screwed up my lights for a day while I tracked it down.

Frustraiting to say the least.

Re: Wiring Issues
 

So heres a new problem. Got power to the tailights. No brake lights. Only one reverse light works and the parking lights are top and bottom now. Im so ready to get rid of this truck. Could it be the brake switch connected to the pedal?

Re: Wiring Issues
 

the park lights should be on the top and bottom only the brake light, lights on the bottom.

Re: Wiring Issues
 

i had the same problem on my 94 gmc the headlights works and nothing else it happened twice the first time was the switch itself and the second was a wire was rubbing against the frame in the back and wore through so id look for bad wires or a bad switch

Re: Wiring Issues
 

I Dont have brake lights and on my left side the parking light is the top bulb and on the right its the bottom bulb.