Brake lights and hazard quit working

This is at the rear of the truck? You never mentioned that at all.

Was there a cap on the back of the truck at some point?


Roy

You saw it in the picture of the connector. Cap you mean like a camper type cover? I have only had the truck 2 years. It has a trailer harness.

Okay, at this point you need a shop that is good at electrical work. You have a harness issue somewhere that was modified or changed by someone and needs to be traced to find out why you do not have rear brake lights.

Roy

I had them they just quit. I do appreciate your time. Thanks Roy and everyone that helps. Dan

Hello again.

I caught this post toward the end of the repair. What was fixed and what still is the issue and needs to be repaired? Just want to be on the same page. Thanks again for using 2CarPros and Happy Holidays.

Danny-

i don't have the always hot wire at the brake light relay fuse box under the hood. replaced the brake switch the multi switch. i took the white wire that tested hot when the brake on. i spliced it into my brake wire and now have brake light and two hot in the relay box with the brake on. but lose my right turn signal. i did take those two wires apart. i just wanted see if it would tell me anything. bottom line my brake light on the cab works all light work but tail brake light.

Going back to the start, do you have power out of the multifunction switch to the wires to the rear tail lights with the brake pedal depressed?

Roy

yes.

Okay, if you have power out of the switch, then it is wiring to the rear lights. It is a direct path to the rear sockets.

Did you test for power to the rear sockets?

Roy

all lights work. the brake lights work. i wired them to my cab brake light they work then.

What happens when you use the turn signals?

Roy

all lights work exactly the way they should, not the brake light.

in the brake relay wiring is one wire hot all the time?

They should not if you went around by tying into the 3rd light.

Going back to the diagram, there is a fuse that supplies power all the time to the relay. The white wire feeds it only after the pedal is depressed.

Check the diagram I posted in the beginning.

Roy

that fuse is good. so the cab light does not go through the relay?

No, if you look at the diagram, it comes from the brake light switch white wire.

Roy

that's the one that hangs down in the picture at rear from the harness. is that right?

No, this is all from the front by the brake light switch. That wire was added by someone for some reason.

Roy

there is a surge brake in it.

Surge brake is like a master cylinder that activates the trailer brakes.

The only electricity you have for the trailer is the lights. That is the white wire at the back that you have hanging free.

Roy

the white wire is the one i connected to the rear brakes wire to make them work, but i lost my right turn signal when i brake. it was different then i did with the cab light.

You have a wiring issue with the rear lights from the multifunction switch. I mentioned that to you before. There is no bypassing and wiring around the issue and having all the lights work the way they should.

I know you had it to several places that do not know much about electricity but you do need help with this from someone who knows electricity and how to trace the wiring.

Roy

i agree, Danny ask me a question i thought he might have an idea. i am retired and $140.00. an hour is not possible.

There is no wiring around it at all.

I would look for a harness from the switch to the back lights. You will need to call salvage yards to see if anyone has it.

Roy

the switch?

Yes, from the multifunction switch to the rear lights.

Roy

so from what plugs in to the switch to the rear. that's what i need?

That is correct.

Roy

again thanks. so there must be multiple truck that have that harness. any where i can find that info?

You are welcome.

Try going to www.car-part.com. good site with all kinds of parts.

Roy

am i looking for the body harness?

You are looking for the under-dash harness and external harness to the rear of the truck.

Roy

i am.

Did you try www.car-part.com? You may have to call the supplier to be sure you are getting the correct harness.

Roy

i am looking at the junkyard. It's about the money.

Okay, got it.

Roy

Hello again.

I've attached picture information below of the Chevrolet truck wrecking yard I use here in Southern California. Ask for Tom he knows his stuff and I'm sure he will have your wiring harness and can ship if you don't find it in your area. Hope this helps and thanks again for using 2CarPros.

Danny-

Thanks man.

I am in Vegas, it a 4 hour drive.

You're welcome!

Give him a call I'm sure his business can ship it to you if you can't find it in your area. Thanks again for using 2CarPros.

Danny-