7-Wire Trailer Wiring question

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7-Wire Trailer Wiring question

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7-Wire Trailer Wiring question - 5/13/2008 10:22:17 PM

canuckh3

Posts: 16
Joined: 6/17/2007
Status: offline

Hi all...long time lurker...second time poster. This site has been a big help, over the year I have owned my unit! I have a question about installing a trailer brake controller and a 7-wire plug outback on a 06 H3 Adv. Package with no Trailer package. I have searched the forums and all I could find is this...

"Why no 7-Wire round plug?!
For some reason, Hummer thought it would be a wise idea to only run 4 wires. However, don't fret, if you need a 7-wire round plug, you are most likely pulling too big of a trailer! Most trailer/boat/PWC applications require the 4-flat wire plug."

Well, I want to pull a approx. 3000 lb trailer...and it does have a 7-wire connection. Has anyone installed a controller and a 7 wire plug on a unit without the trailer package.

And elsewhere, I read about the available wires to the right side of the steering column that on the units with trailering packages have already for the controller...but since I don't have the package, is there a harness I can get to make one work?

Someday if the weather is half decent, I'll gets some pics of the truck and post...

Post #: 1

RE: 7-Wire Trailer Wiring question - 5/14/2008 4:00:55 AM

alphadogg

Posts: 358
Joined: 12/30/2007
Status: offline

Welcome to the forum. What you need is the wiring harness that comes standard on trucks with the towing package. That can be bought and installed at your dealer or most trailer sales places. That will give you the ability to use the round 7 pin plug so you can use a brake controller.

(in reply to canuckh3)

Post #: 2

RE: 7-Wire Trailer Wiring question - 5/14/2008 9:15:25 AM

canuckh3

Posts: 16
Joined: 6/17/2007
Status: offline

Thanks....I'll have to check out a couple of places here...

(in reply to alphadogg)

Post #: 3

RE: 7-Wire Trailer Wiring question - 5/14/2008 11:35:03 AM

RealJeep

Posts: 724
Joined: 7/30/2007
From: Lakeland, Florida
Status: offline

The non-trailer pkg equipped H3 can be a pain to wire in!
Also if I'm not mistaken, the plug that comes with a stock trailer package is a 4 wire plug BUT the inside is wired for 7 wire. All you need to do is buy the different plug and you're good to go. It also has the trailer brake tap built in so no need to go out and waste your money on an after market one.

< Message edited by RealJeep -- 5/14/2008 11:46:11 AM >

(in reply to canuckh3)

Post #: 4

RE: 7-Wire Trailer Wiring question - 5/14/2008 8:53:51 PM

canuckh3

Posts: 16
Joined: 6/17/2007
Status: offline

Well found something interesting tonight...even though I don't have the trailering package, I do have the controller wiring under the dash...taped to the courtesy light.

Also I found the four wire blunt cut wires when you open the rear door between the body and the bumper, just need to find the other(s) namely the blue wire...anyone have a clue where this may be at the back?

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< Message edited by canuckh3 -- 5/14/2008 9:49:43 PM >

(in reply to RealJeep)

Post #: 5

RE: 7-Wire Trailer Wiring question - 5/15/2008 3:24:49 AM

ozHummer

Posts: 43
Joined: 4/19/2008
Status: offline

I wired my own plug using the H3's trailer harness. This was a 14 pin female plug zip tied just behind the bumper on the LHS of the vehicle. I do have the 2008 Australian RHD H3. The harness even has 40A powerleads, reversing leads, all standard leads, ignition lead and engine ground. It's fully loaded.... So I'm not sure what the story is with the 4 lead version you guys talk about, but we got 14!.... Want Pics ?

_____________________________

Cheers

KD

(in reply to canuckh3)

Post #: 6

RE: 7-Wire Trailer Wiring question - 5/15/2008 9:14:05 PM

canuckh3

Posts: 16
Joined: 6/17/2007
Status: offline

Installed a Hidden Hitch tonight, and looked more into the wiring situation. Looks like I'm running wires to the back, as the some of the wires I found last night under the dash dead end into a connector under the hood just behind the battery ...guess the towing package uses a different harness from that point to the rear. Alphadogg was right...

< Message edited by canuckh3 -- 5/15/2008 9:23:59 PM >

(in reply to ozHummer)

Post #: 7

RE: 7-Wire Trailer Wiring question - 5/16/2008 5:43:49 AM

RealJeep

Posts: 724
Joined: 7/30/2007
From: Lakeland, Florida
Status: offline

quote:

ORIGINAL: canuckh3

Installed a Hidden Hitch tonight, and looked more into the wiring situation. Looks like I'm running wires to the back, as the some of the wires I found last night under the dash dead end into a connector under the hood just behind the battery ...guess the towing package uses a different harness from that point to the rear. Alphadogg was right...

Oh yea of little faith. And you first doubted the Dogg? How'd that work out for you?

(in reply to canuckh3)

Post #: 8

RE: 7-Wire Trailer Wiring question - 5/20/2008 9:17:19 AM

canuckh3

Posts: 16
Joined: 6/17/2007
Status: offline

Saturday I spent in the garage wiring up my 7-way socket and trailer brake controller...turned out it wasn't as bad as I thought not having the wiring in the factory harness.

All I did was purchase about 16' of split loom, some 12 gauge wire and paralleled my new harness along the factory one to the rear. In my new harness I added a fused 12volts live all time circuit, and the trailer brake wire.

At the rear I tied into the existing four-wire circuit, the only thing I don't have is the backup light circuit, I didn't have the time to root around and find & splice that circuit, but I don't think I will need it anyway. Everything was live on the factory harness for the controller under the dash which was a bonus. I used a four pin Molex connector so that I can remove the controller when it's not in use.

Now I need to find a travel trailer I can pull with the 3.

(in reply to RealJeep)

Post #: 9

RE: 7-Wire Trailer Wiring question - 5/23/2008 7:31:32 PM

lepack

Posts: 4
Joined: 10/10/2007
Status: offline

canuckH3,

Did you end up buying a GM harness then? Is there a 3rd party harness available for the H3? Thanks!

< Message edited by lepack -- 5/23/2008 7:39:48 PM >

(in reply to canuckh3)

Post #: 10

RE: 7-Wire Trailer Wiring question - 5/23/2008 8:30:56 PM

H3Dude812

Posts: 74
Joined: 5/7/2008
Status: offline

I would assume that with the factory 7 pin, every pin is hooked up, correct? I need the back up light for my boat trailer brake disconnect.

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(in reply to lepack)

Post #: 11

RE: 7-Wire Trailer Wiring question - 5/23/2008 9:33:17 PM

canuckh3

Posts: 16
Joined: 6/17/2007
Status: offline

lepack...I checked with my dealer and they couldn't find a part number for a harness, so...I ended up creating my own with split-loom and I tie-wrapped it along side the factory harness that follows along the drivers side frame. It's no big deal, I added 2 wires - the blue trailer brake circuit and a 12V hot all the time circuit for trailer interior lights etc. Like I said, I didn't bother with reverse lights, its in the factory harness and I suppoe it would be easy to tap into ... I believe from what read here and there, it's a light green wire.

h3 dude, I would assume that the factory 7-wire would be wired to the standard config. Easy to compare your H3 socket to your trailer wiring with a cheap test light type probe, assuming you know how the trailer is wired.

< Message edited by canuckh3 -- 5/23/2008 9:45:28 PM >

(in reply to H3Dude812)

Post #: 12

RE: 7-Wire Trailer Wiring question - 5/25/2008 8:34:29 PM

lepack

Posts: 4
Joined: 10/10/2007
Status: offline

Thanks canukh3, that makes sense.

One more question. I went hunting for the blue brake wire that dead-ends in a connector behind the battery as you suggest. Is this it?

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< Message edited by lepack -- 5/25/2008 8:52:13 PM >

(in reply to canuckh3)

Post #: 13

RE: 7-Wire Trailer Wiring question - 5/26/2008 12:13:52 PM

canuckh3

Posts: 16
Joined: 6/17/2007
Status: offline

Yes it is...to confirm, there should be a light green wire on top of it at the connector point. From there, I cut the blue flush with the connector and used a good butt splice into my harness. If you didn't want to go that extreme you could fish that wire out and use one of these;

http://www.tessco.com/products/displayProductInfo.do?sku=73594&eventPage=1

(in reply to lepack)

Post #: 14

RE: 7-Wire Trailer Wiring question - 5/26/2008 9:32:04 PM

lepack

Posts: 4
Joined: 10/10/2007
Status: offline

Thanks for you help!