Electrical Work.

Discussion in 'GM Electrical Tech' started by Conlan Rose, Dec 21, 2012.

  1. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    Ok I will open up the wire loom and look tomorrow. I still don't know where the trailer brake wire it but it must be near. I didn't really look I just took the pictures. One of the looms goes directly in to the fuse box and then to the interior fuse box. The big ass wire is power to the box. Btw do you know what that connector is for?
  2. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    I'm hoping you don't have to do a splice or, worse, run your own wires back. I say that because 96 is one of those years where I'm just not sure they had the pre-wiring for brake controllers standard on all the vehicles. However, if you have a tow package in your RPO codes I'd expect the wiring to be there.
  3. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    Based on the fact that the wires exist in the back by the hitch and I have the RPO code for the trailer package. Only pain thing is the under daze wire block doesn't have a spot for the controller and it must be wired in by "hand". Luckily there is a spot for the stop lamp switch in the block.
  4. Jamm3r

    Jamm3r Member 2 Years 100 Posts


    Sorry I didn't read carefully and thought you were just looking for the aux power connector.

    The brake connector is wired to a connector block on the inside of the firewall. You can get a mating plug from GM or from places that sell trailer brake controllers. If I remember right it's up quite high above the parking brake pedal and part of a larger fuse/relay block but I may be mixing up nbs and obs trucks in my head.

    The mating plug will bring out everything you need for a brake controller - the brake line to the trailer, power, brake switch, and ground. I don't think you get instrument lights but most modern controllers don't use that.
  5. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    Its ok [MENTION=53334]jamm[/MENTION]3r we all have those moments. I think I need to create the power lead for the controller but I know the block has the brake switch. I need to ask [MENTION=23100]KidHauler[/MENTION] what he did he has a basic write up he gave me, but I have more questions.

    This block? To my knowledge The brake switch is the port NAT which is behind the blue, tan, and green wires.

    2012-05-21_19-33-08_221.jpg 2012-05-21_19-32-31_37.jpg

    KidHauler gave me this pic of his:
  6. KidHauler

    KidHauler Epic Member 5+ Years 500 Posts

    All right, I'm up to speed.
    In my picture, in the NAT socket, the red wire is the cold side of the brake circuit, the white wire is the parking light circuit. Sooo, on my truck, the red wire goes to the brake controller brake wire, and the white wire feeds my aux fog lights.

    Now, for your trailer harness: look at the bracket attached to the firewall, under the brake booster, this is where my wires are located. What I can't remember is if this where I found them originally.

    There should be a blue and orange wire taped - either to that bracket, or in the frame rail where it curves up under the footwell/firewall on the drivers side. It's been awhile since I did mine, so I'm sorry for the memory loss, but I'm leaning towards the frame rail location. There should be enough wire to finish the run to the fuse block and cabin, so it's a pretty big loop.
    Anyway, the orange wire needs to be terminated and put to one of the 30a posts in the underhood fuse block - that's your trailer power. The blue goes through the firewall grommet and to your brake controller.

    Hope this helps. Also, I used an aux. contact in the seven blade plug to run a backup light to the back of my camper. It's cold here, too, so you'll have to wait for that one:)

    Good luck,

    forgot this [MENTION=52248]Conlan Rose[/MENTION]
  7. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    Thank you very much [MENTION=23100]KidHauler[/MENTION] :smile: I will have to wait for "warmer" weather to find the wires and attach them appropriately. I already have the center contact in the trailer wiring harness as a back up light lead. It is powered by a relay that also feeds my back up light.
  8. KidHauler

    KidHauler Epic Member 5+ Years 500 Posts

    Yeah, I saw that earlier in this post. I guess I don't have to crawl under mine tomorrow!
  9. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    Glad to see you around again, you had been absent for a while.

    Ok, in other new for my electrical mods the 4 awg lugs are in just waiting on the 1/0 lugs. Then need to measure old leads and cut new ones to the right size and attach. That will be next weeks project.
  10. KidHauler

    KidHauler Epic Member 5+ Years 500 Posts

    Good luck with that job. The weather here is dry, but cold, and probably headed towards you. Do you have a garage for these projects?

    We've had a lot of OT lately, and I have a few side jobs, so I wasn't at the computer alot - or the TV, washing my truck, eating dinner....

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