Trailer wiring

Discussion in 'Towing & Trailer Tech' started by CowsPatoot, May 12, 2011.

  1. CowsPatoot

    CowsPatoot Member

    I have a 2001 Z71 with the factory trailering package (regular cab, stepside, every known option other than leather and power seats, 5.3 liter/auto...just in case any of that makes a difference). I have a trailer that I wired myself to use the factory 7 way round plug that my truck has. Everything works properly with just the standard running lights, brake lights and turn signals on the trailer.

    Now for the desired grandfather gave me a small electric winch to put on the trailer. But...what is the best way to power it? From the wiring diagrams I was looking at (, it appears that the upper left pin is a 12v+ for accessories. Will this provide enough power for this small winch? I don't know how many amps it pulls, but it appears to have an 8-10 gauge power wire on it (I am not the best at judging gauges). I would like to avoid adding a battery to the trailer...but if I have to, this wire could at least be used to charge it, correct?

    Second additional question. I currently don't have the brakes wired up on the trailer, but would like to. Does my truck have a factory brake controller for the trailer (lower right blue wire in those diagrams)? I have never assumed that Chevy ran the wires simply because there is a plug at one end.

    I also question the backup lights (future mods to the trailer), but that is easy enough to check with a voltmeter.
  2. stephan

    stephan Rockstar 4 Years 5000 Posts

    Since your winch has an 8 or 10 ga power wire, you should have the same to power it & the trucks trailer wiring is not going to be up to it. Tail & T signals run 16 ga or maybe 14 ga at best. You could run a separate 8-10 wire all the way from the truck battery, but should probably be bigger because the length of the run (15-16 feet?) This much run will cause resistance & heat in the wire if it's too small. As far as charging an on trailer battery through the trailer plug again the trailer plug wiring is not up to the guage you need to carry this current for this distance. Look at the wire on your trucks alternator that runs to the battery positive. You will need at least this guage wiring to run to the trailer to charge the winch battery, & probably should be larger guage due to the 15 foot long run as opposed to the 5 foot run from the alternator to the battery under the hood.
    Sorry, I don't know if your truck has a brake comtroller
  3. CowsPatoot

    CowsPatoot Member

    Wanted to stop by and thank you for your reply, and add a bit of info in case this is found in searches. I finally pulled out the wiring harness that has been in my glove box since I bought the truck and read the paperwork with it. It is the harness with instructions on how to wire in a brake I think it is safe to assume that I do not have one built into the truck.

    As far as the 12V accessory plug...I found this thread on another forum:

    To paraphrase that post:
    Per Hook'em Horns - "It's a 40amp feed to recharge your trailer's battery(s). All RVs run on a 12-volt system and have a battery (or multiples), as well as a large trailer mounted winch for a car hauler."
    and per lugnut5 - "There is a dummy fuse marked B+ in the fuse box in the engine compartment. It was located in the top left of the pannel. Owner's manual says "DO NOT INSTALL FUSE"."

    Note that the power wire for the winch is 8-10 gauge, but it is also about 30' long.

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