Trailer wiring harness (Full Version)

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Trailer wiring harness

  

SeaGar -> Trailer wiring harness (6/27/2006 7:21:42 PM)

First, yes I am a dumb a&$. I can not find the harness where my trailer T connection goes. I have looked everywhere,under, over, inside, outside of my H3. I do have a base model, don't know if GM didn't put it in, like my floor mats. I mounted the hitch in 20 min. 2 hrs later still looking for this harness. Any one else have a Base model that has located this harness. Thanks for the help.
Wayne

  
Dennis -> RE: Trailer wiring harness (6/27/2006 10:33:19 PM)

Hey Wayne..No dumbases here..we all ask questions, someone is bound to know the answer here so ask away.

Are you talking about this?...You should have one as it's part of the trailer hitch, but strange enough it is sold seperately..So maybe that is something you should discuss with your dealer about..

[image]http://i16.photobucket.com/albums/b47/Atwater/MVC-019S.jpg[/image]
[image]http://i16.photobucket.com/albums/b47/Atwater/plug1.jpg[/image]

Linus Gump -> RE: Trailer wiring harness (6/27/2006 10:47:28 PM)

I believe he is installing an aftermarket hitch. If that is the case, I would say to follow the license plate wiring up until you come to a connector somewhere near the frame. I have an exploded view showing all of the factory parts for the towing package, and that is where it shows the factory wiring tying into the rest of the vehicle harness.

Dennis -> RE: Trailer wiring harness (6/27/2006 10:50:46 PM)

Oh[&:]

SeaGar -> RE: Trailer wiring harness (6/28/2006 3:19:40 PM)

Thanks guys,
Yes I did install a aftermarket hitch, I followed the wiring harness back without finding the connector to tie into. Where did your exploded pic show it. It should be near the rear bumper but it's not there on mine.
Wayne

importkiller -> RE: Trailer wiring harness (6/28/2006 4:57:29 PM)

Best way I have found on previous trucks was to follow the drivers side brake light wires, they will join a connector. On my other gm's the connector was always near the frame or up under the spare tire area (muffler area on the H3) On my Jeep the connector was actually inside behind one of the interior pieces on the drivers side rear. I'm going to be hooking my boat up to the hummer tonight anyway, I'll look around for it and let you know.

NJTEX -> RE: Trailer wiring harness (6/28/2006 7:30:54 PM)

Can you please post a picture of your installation? I'm in the same boat you are in without the factory option and need to add a hitch soon. Did you go Draw-Tight or Hidden-Hitch.

If you open the rear hatch (door?) and look down between the rear of the truck and the bumper, you'll see a cable harness wrapped in a corragated black plastic sheath. The sheath has a split in it and the trailer wiring is tucked inside ready to be pulled out. That's the way it is on my Lux model anyway.

importkiller -> RE: Trailer wiring harness (6/28/2006 8:46:01 PM)

is the hitch a dealer installed item or factory? I know when I worked for a chevy dealer here we used to install them as well as nerf bars and running boards on all chevy trucks. If it is a dealer installed item then all models will have the wiring there for the trailer harness.

SeaGar -> RE: Trailer wiring harness (6/28/2006 9:06:39 PM)

Thanks All. I found my harness, no connector, just 4 loose wires. NJTEX was right, I'll have to splice my connector to it. It was between the rear of the hummer and the bumper. I went with a draw-tite hitch $181 inc shipping and harness.
Wayne

importkiller -> RE: Trailer wiring harness (6/28/2006 9:15:40 PM)

There should be 7 wires if I'm not mistaken, gm's come with a 7 round connector. If all your using is a 4 flat then you'll be ok with what you found but if you tow a trailer that has built in surge brakes you'll need a (+) reverse lead to lockout the trailer brakes when you backup.

importkiller -> RE: Trailer wiring harness (6/28/2006 9:17:51 PM)

just saw your pics...I guess I was mistaken. Thats kinda strange that they wouldn't have the entire wire bundle for the harness there.

SeaGar -> RE: Trailer wiring harness (6/28/2006 9:29:57 PM)

Ya, GM saved 17 cents by using 4 wires and not 7.

NJTEX -> RE: Trailer wiring harness (6/28/2006 11:25:15 PM)

Thanks for posting the Pics. The Draw-Tite hitch looks nice and clean and high enough. Think I'll do the same. I just don't want to cut the rear bumper to install the OEM hitch. Here in the North East it's just an open invitation for rust no matter how well you think you've sealed the cut edge.

I also noticed that Draw-Tite just introduced a matching front mounted receiver. Seems like a nice combination and a confidence builder if you have a good portable winch stowed in the trunk.



Barry Weeks -> RE: Trailer wiring harness (8/7/2006 11:01:48 AM)

I JUST HOOKED UP MY BIKE TRAILER LAST NIGHT WHICH IS WIRED TO CODE. IT HAS A FLAT 4 POLE PLUG. I PULLED IT UP THRU THE SUPPLIED 7-4 WAY PLUG. NOW WHEN I PRESS THE BRAKES, ALL TRAILER LIGHTS GO OUT. IS THE H3 WIED TO CODE OR ANY SUGGESTIONS?
THANKS

HummerGuy -> RE: Trailer wiring harness (8/7/2006 12:41:02 PM)

I installed my own trailor hitch wiring harness. The factory DOES have the four trailor hitch wires loose under the bumper, with shrink tubing around each of the four wires (as you found). If you want a seven-wire hookup, there are adapters that you have to buy, BUT you won't have the functionality of a real heavy-duty braking system unless you buy a third-party brake towing system that applies pressure to the trailor's brakes based on how hard you stop. You probably will never need this on an H3 though because it can't tow all that much weight to really need the system, unless you are maxing out at 4500 lbs. I'm not an expert at it, but I did alot of research a few months ago. I toed a few things and the brakes on the H3 are so good, I couldn't even feel the trailor behind me.

  

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