Wiring For Trailer Brake Controller With Max Trailering Package

Gozer · April 24, 2007

Has anyone hooked up a trailer brake controller to their 2007 Sierra/Silverado with NHT (Max Trailering Package)? Does the NHT package include a harness, or are there just pigtails stashed under dash?

Wondering if I can tackle this install myself when my truck comes in.

Thanks!

sonjaab · April 24, 2007

GO.........Sadly no more plug n' play on the 07s.

Doesn't your new rig already have a built in trailer brake controller?

My soon to be delivered 07 GMT-900 does. It was a $250? option

on top the trailer tow pkg. option charge................

Anyhoo....The wires are blunt cut and down by the underdash fuse

center. There are pics and instructions around here somewhere.

Will find and post !.........geo

Gozer · April 24, 2007

GO.........Sadly no more plug n' play on the 07s.
Doesn't your new rig already have a built in trailer brake controller?

My soon to be delivered 07 GMT-900 does. It was a $250? option

on top the trailer tow pkg. option charge................

Anyhoo....The wires are blunt cut and down by the underdash fuse

center. There are pics and instructions around here somewhere.

Will find and post !.........geo

No built-in brake contoller on the 1/2 tons that I'm aware of. The NHT package mentions: "electric trailer brake wire harness" among the various items included. Guess I'll find out when/if my truck ever gets in.

redwings10 · April 24, 2007

Hi,

I am new to this forum and have a ? about wiring my 04 GMC 1500 with a heavy duty tow package.

I got a wiring harness with the truck to plug into wire box under the dash for a brake controller.

I plug in and put in the 40amp fuse in the "stud 1" like the direction told me and wire the Odyssey brake controller. The red wire from the plug to the controller does not have power to the wire box under the dash. Ran a jumper wire from battery and brake controller has power. Dealer told me there is no wire from from under the hood to the wire box under dash. Am I missing some thing or did GMC save $1.00 by not putting this wire in.

I am not trying to hijack this tread just need info before I take my truck to the dealer and tell them what a lie the wiring diagram is.

Thank you for helping me,

Tom

plainvanilla · April 24, 2007

my 07 old body style 1/2 ton had the harness/pigtail in the side pocked of the drivers door.

You get your brake controller take the wiring harness hook up about 4 color-coded wires using the directions on the brake controller, about a 5 minute job and plug the other end of the harness into a slot made exactly for it and nothing else will fit there. It is on a panel up under the dash on the left side near the kick plate.

I spent more time getting the settings on the controller adjusted than I did doing the wiring.

If you didn't get the harness, I'd go back to the dealer and make them give you one.

sonjaab · April 24, 2007

TOM....your best off doing a search. Gm does some weird things.

My bud is having controller issues with his 07 GMT 900 1/2 ton.

He had to hook up a unhooked wire that was loose under the underhood

fuse center as well as put a maxifuse in stud#1..............

My 04 was plug n' play and the only reason for the maxifuse in

stud1 was for the aux. power (hot) wire in the rear wiring harness

not the controller................

My 07 2500 NBS has the factory controller.........

Hmmmm.........geo

redwings10 · April 24, 2007

I would like to say thank you to both of you for you fast reply

Just pisses me off all other wires work but no power to this red wire. My father-inlaw has a 04 chevy 2500 HD and told me plug and play for his brake controller.

If I have to run a wire and fuse no big deal. Just time and one mad ower of a GMC truck.

Thanks again for the fast replies

Tom

sonjaab · April 24, 2007

Tom....Still haven't found the post with the pics of the wires!

But my bud is going thru this with his nbs 07............

Read this post on which wire needs to be hooked up to the fuse

center to power up the brake controller:

http://www.gm-trucks.com/forums/index.php?...er+brake+wiring

sonjaab · April 24, 2007

TOM....heres the link with the pics and GM wiring colors:

http://www.gm-trucks.com/forums/index.php?showtopic=64063

plainvanilla · April 24, 2007

I would like to say thank you to both of you for you fast reply

Just pisses me off all other wires work but no power to this red wire. My father-inlaw has a 04 chevy 2500 HD and told me plug and play for his brake controller.

If I have to run a wire and fuse no big deal. Just time and one mad ower of a GMC truck.

Thanks again for the fast replies

Tom

Hey wait a second.

They were telling me at the RV center last month about a guy with a OBS 07 1/2 ton that the factory supplied wire harness had two wires in the wrong spots and they couldn't get the controller to energize.

He took it back to the dealer and luckily someone figured it out and switched the two wires back.

Turns out the factory controller harness was assembled in Mexico....

sonjaab · April 24, 2007

GUYS......Thats why a test light and these forums are your best friends !

mljenkins · April 24, 2007

'06 WT 1500 w/ HD trailering package came with the harness in the glovebox. Bought a fuse at the auto store, put it under the hood where the sticker on the side of the harness said, wired the pigtail of the harness to the controller, and plugged the pigtail in, all was good.

Later purchased a Tekonsha Prodigy controller with a harness and plugged it in the same spot, no issues. I highly recommend the brake controller. Pulling about 6000-8000 lb gooseneck behind a 1/2 ton and needed to make sure I had good braking.

Someone posted a wiring diagram of the SEO and trailer harness connector for the 2006 in a post here:

http://www.gm-trucks.com/forums/index.php?...st&p=373514

If the 2007 is the same, it may help troubleshoot any wiring issues with the harness.

Looks like only the 2500 and 3500 models will have the integrated brake option according to Chevy's site.

Good luck.

2017HD · April 25, 2007

Well according to my 2007 Siverado manual the Basic Trailer Wiring consists of a seven wire harness and no connector plug. The heavy duty wiring harness adds the connector in the bumper. The wires include: Yellow- left turn/stop Dark Green - right turn/stop Brown - tail lamps White - ground Light Green - back-up lamps Red - battery feed Blue trailer brake

The battery and trailer brake wires have fuses installed in the underhood electrical center, but the wires are not connected. They should be connected by your dealer or a qualified service center.

Electronic Brake control wiring provisions are included with your vehicle as part of the trailer wiring package The instrument panel contains blunt cut wires near the data link connector. the harnass contains four wires - dark blue- brake signal to trailer connector Red/Black - Battery Light Blue/White- brake switch White - ground.

It sounds like they did away with the plugs and adaptors and allow you to connect directly to the wires.

A further note for the 2500 and 3500 with the integrated brake controller, the blunt connect wires still exist, but are not attached to anything in the harnass.

MS3DALE · April 25, 2007

Here's a couple bulletins on these issues......

Document ID# 1866253

Subject: Information on Electric Trailer Brake Controller Wiring - Towing, Tow #06-08-45-008 - (10/10/2006)

Models: 2007 Cadillac Escalade, Escalade ESV, Escalade EXT

2007 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

Some customers may have questions on how to connect an electric trailer brake controller or where the brake controller pigtail harness is located.

Starting with the new 2007 full size utilities and pickups, there is no longer an electric trailer brake controller pigtail harness.

The trailer brake controller wiring is now part of the Instrument panel wiring harness and the blunt cut wires are located under the left instrument panel, behind the data link connector. There are four blunt cut wires in this harness as described below.

Wire Color

Circuit #

Description

Red/Black

242

12 Volt power supply (30A stud #2)

Dark Blue

47

Trailer brake output voltage

White

22

Ground

Light Blue

6311

Stop light input

The Red/Black circuit 242 must be connected to stud #2 of the 30 Amp fuse of the UBEC. This wire is located between the left fender and the UBEC (1). Refer to Trailer Connector/Provision Schematic in SI for document information on the trailer brake control-- Domestic.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

Here's one if you have a 2500/3500 with the factory brake controller but still want to add your own.....

Document ID# 1947926

Subject: Adding Aftermarket Trailer Brake Controller With Integrated Trailer Brake Controller - keywords connector electric hydraulic itbc tow towing wire wiring #PIT4332 - (03/30/2007)

Models: 2007 Chevrolet Silverado

2007 GMC Sierra

With RPO JL1

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some owners may request to have an aftermarket trailer brake controller added, in lieu of the factory ITBC (Integrated Trailer Brake Controller) RPO JL1. This request may be made if the trailer being towed is equipped with electric over hydraulic brakes. This style of trailer brake system is not supported by the ITBC. An aftermarket trailer brake controller can be installed to operate with the electric over hydraulic trailer brakes, however the factory installed ITBC system will be disabled.

Recommendation/Instructions:

To install an aftermarket trailer brake controller use the four blunt cut wires near the data link connector and make the following changes to the vehicles harness:

Four Blunt Cut Wires:

Header

Dark Blue

Circuit 47

Brake Signal to Trailer Connector

Red/Black

Circuit 242

Battery Power

Light Blue/White

Circuit 6311

Brake Switch Input

White

Circuit 22

Ground

Vehicle Changes:

The Red/Black circuit 242 must be connected to stud #2 of the 30 Amp fuse of the UBEC. This wire is located between the left fender and the UBEC.

Locate connector X126 near the UBEC (Doc ID 1849049). Circuit 47 from the blunt cut wires near the data link connector will end at connector X126 terminal "G". Obtain enough Dark Blue 12 gauge wire to run from X126 to the 7-way trailer connector at the bumper. On one end of the Dark Blue wire attach terminal part number 15304732 located in Delphi Tray 8 and insert into X126 "G". Run the Dark Blue wire in its own conduit along the frame to the 7-way trailer connector at the bumper. Remove circuit 47 from the 7-way trailer connector terminal "C" and tape the bare terminal and attach to harness. Attach terminal part number 12110853 located in Delphi Tray 4 to the other end of the Dark Blue wire and insert into the 7-way trailer connector terminal "C".

Note: This procedure will not result in any Trailer Brake related display messages to be set. However, ITBC diagnostics will continue to function. If an ITBC fault is detected, a "Service Trailer Brake System" message will be displayed on the DIC and an appropriate DTC will be stored in the ITBC module. The operator will still be able to adjust gain and access the "Trailer Gain / Output" display page in the DIC. However, the factory installed ITBC system will not sense a trailer connection and will not provide output to the trailer.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.