Chevy

Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

This answer was rated:

Need wiring diagram for electric trailer brakes on a 2003 GMC 1500 Sierra pickup

I am trying to trace...
I am trying to trace the wiring for electric trailer brakes on a 2003 GMC 1500 Sierra pickup, cheep model. It has trailer ready wiring, i.e. it has some wires run to the rear of the pickup for lighting. It also has the trailer brake moduel under the dash on the left side. My problem is the wiring from there to the rear of the pickup. I thought if I had the wiring diagram, I could resolve my problem.

Sheldon
Show More
Show Less
Ask Your Own Chevy Question
Answered in 34 minutes by:
10/24/2008
GM-Frank
GM-Frank, ASE Master Certified
Category: Chevy
Satisfied Customers: 431
Experience: 37 Years Automotive Diagnosis and Repair. 25 Years of General Motors Dealer Experience
Verified

 

HEllo Sheldon,

 

Although your's may not exhibit this condition, the technical bulletin may help.

 

Bulletin No.: 02-05-22-004C

Date: April 05, 2005

TECHNICAL

Subject:
Trailer Brakes Applied When Headlights/Park Lamps Are On, Brake Controller Illumination (Modify Brake Controller Wiring Harness)

 

Models:
2002-2005 Cadillac Escalade, Escalade EXT
1999-2005 Chevrolet Silverado
2000-2005 Chevrolet Suburban, Tahoe
2002-2005 Chevrolet Avalanche
1999-2005 GMC Sierra
2000-2005 GMC Yukon, Yukon XL
2003-2005 HUMMER H2

 

Supercede:

This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 02-05-22-004B (Section 05 - Brakes).

Condition

Some customers may comment that when the headlamps or park lamps are on, the brakes on the trailer are always applied, or that the back lighting for the trailer brake controller only illuminates when the brakes are applied.

Cause

The cause of this condition may be due to wiring changes within the vehicle electrical system for the 2003 model year.

Correction

 

graphic

 

Inspect the brake controller wiring harness jumper that is plugged into the vehicle relay block-body. The relay block-body is located under the left side of the instrument panel near the left kick panel, behind a plastic cover.

The 1999 though early 2003 wiring harness jumper that plugs into the relay block will have a reddish/brown 6-way connector and a tag with the last four digits of the wiring harness part number. Second design 2003-05 may have a white plastic connector with part number 5418 as well.

^The 1999 jumper is/was P/N 12171982 with a pink/purple tag identifier of 1982. This number has been superseded to 15366255, with a pink/purple tag identifier of 6255.

 

^The 2000 jumper harness is P/N 15366255. The pink/purple tag identifier is 6255.

 

^The 2001-2002 jumper is P/N 15086884. The orange tag identifier is 6884.

 

^The 2003-05 jumper is P/N 15085418. The orange tag identifier is 5418.

 

 

graphic

 

When transferring the brake controller with the wiring jumper attached from a 2001-2002 vehicle to a 2003-05 vehicle, a change to the jumper harness connector must be performed.

 

graphic

 

The information shown is for the 1999-2002 wiring harnesses and for the 2003-05 wiring harness.

To modify a 12171982, 15366255 or 15086884 harness for use in a 2003-05 vehicle, switch the wires in cavities "A" and "D".

To modify a 15085418 harness for use in a 1999-2002 vehicle (see model list at the front of this bulletin for applicable models), switch the wires in cavities "A" and "D".

Warranty Information

When the correct wiring harness P/N is matched to the specific model year of the vehicle, everything works properly.

 

I'll forward you a bit more shortly.

 

Frank

Ask Your Own Chevy Question

 

Here's more Sheldon,

 

graphic

 

graphic

 

graphic

 

graphic

 

I hope the information I have provided helps.

 

Take Care

 

Frank

Ask Your Own Chevy Question

 

Here's a bit more I found.

 

It appears that the dark blue for the trailer brake wire will be near the IP relay block and will be a blunt cut wire just hanging there.

 

Trailer Wiring Harness
Your vehicle is equipped with one of the following wiring harnesses for towing a trailer or hauling a slide-in camper.

Basic Trailer Wiring
All regular, extended cab crew cab pickups have a six-wire trailer towing harness.

 

The six-wire harness is located at the rear of the vehicle and is tied to the vehicle's frame. The harness requires the installation of a trailer-wiring harness connector, which is available through your dealer.

The six-wire harness contains the following trailer circuits:

  • Yellow: Left Stop/Turn Signal
  • Dark Green: Right Stop/Turn Signal
  • Brown: Taillamps
  • White: Ground
  • Light Green: Back-up Lamps
  • Light Blue: Center High-Mounted Stoplamp (CHMSL)

If you need to upgrade your trailer wiring harness, an additional 2-wire harness and 7 pin universal trailer connector are available from your dealer.

 

Heavy-Duty Trailer Wiring Harness Package

 

Your pickup may be equipped with the eight-wire trailer towing harness. This harness with a seven-pin universal trailer connector is attached to a bracket on the hitch platform.*

* The Center High-Mounted Stoplamp (CHMSL) wire is tied next to the trailer wiring harness for use with a trailer, slide-in camper or cap.

The eight-wire harness contains the following trailer circuits:

  • Yellow: Left Stop/Turn Signal
  • Dark Green: Right Stop/Turn Signal
  • Brown: Taillamps
  • White: Ground
  • Light Green: Back-up Lamps
  • Light Blue: CHMSL
  • Red: Battery Feed
  • Dark Blue: Trailer Brake

If your trailer is equipped with electric brakes, you can get a jumper harness (electric trailer brake control) with a trailer battery feed fuse from your dealer.

If you need to tow a light-duty trailer with a standard four-way round pin connector you can also get an adapter from your dealer.

 

Frank

GM-Frank
GM-Frank, ASE Master Certified
Category: Chevy
Satisfied Customers: 431
Experience: 37 Years Automotive Diagnosis and Repair. 25 Years of General Motors Dealer Experience
Verified
GM-Frank and 87 other Chevy Specialists are ready to help you
Ask your own question now
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a chevy mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask GM-Frank Your Own Question
GM-Frank
GM-Frank
GM-Frank, ASE Master Certified
Category: Chevy
Satisfied Customers: 431
431 Satisfied Customers
Experience: 37 Years Automotive Diagnosis and Repair. 25 Years of General Motors Dealer Experience

GM-Frank is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money.

Todd LRochester NY

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

< Previous | Next >

Meet the Experts:

GM Tech (Cam)

GM Tech (Cam)

Chevy Technician

15,756 satisfied customers

GM Grand Master Technician 2007. 14 years experience.

Gary

Gary

Chevy Technician

9,642 satisfied customers

15 years GM master tech

Tim&#039;s Auto Repair

Tim's Auto Repair

mechanic

8,884 satisfied customers

Have owned a repair shop for 25 yrs.

Dave Nova

Dave Nova

Chevrolet Technician

7,092 satisfied customers

ASE Master Certification. GM World Class Certification

John

John

Master A.S.E Automotive technician

4,071 satisfied customers

A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician

Don - Mo Lurch

Don - Mo Lurch

Auto Mech / Electronics

2,953 satisfied customers

Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics.

Ron Z.

Ron Z.

- Chevy Tech -

2,836 satisfied customers

18+yrs experience. State Inspector and Chevy Diagnostics

< Previous | Next >

Related Chevy Questions
GMC sierra has a "service trailer brake" message. I replaced
GMC sierra has a "service trailer brake" message. I replaced the controller and the message still comes up. I next need to clean the G401 ground connector. I can't find it. Its a GMC 2008 sierra 2500 … read more
fordguy4u
fordguy4u
Automotive Tech
Vocational, Technical or Trade Scho
70 satisfied customers
In which fuse box on 2016 gmc sierra 1500 pickup is the fuse
In which fuse box on 2016 gmc sierra 1500 pickup is the fuse that controls the trailer clearance lights? Engine,Left or right side dash. Stop and turn signals work fine? … read more
GM Bob
GM Bob
Automobile Technician
High School or GED
1,061 satisfied customers
1500 pickup: chevrolet..tail lights..I have a brake light..rear window
I have a 1996 chevrolet 1500 pickup, I have no brake lights in the tail lights , however , I have a brake light over the rear window, where do you think the problem is???… read more
jazzmaster
jazzmaster
LEAD AUTO TECH
Vocational, Technical or Trade Scho
1,124 satisfied customers
RV Trailer brake control lost power. What fuse do I look for
RV Trailer brake control lost power. What fuse do I look for and on what panel? Thanks, Jim… read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
1998 GMC: 1500, my turn signals..hazards..brake pedal..lamps
I have an 1998 GMC sierra k-1500, my turn signals are not working properly. when i use the turn signals on either side they work like hazards just on the rear of the truck,the left ,right, and the thi… read more
Ivan
Ivan
Automotive Instructor
Vocational, Technical or Trade Scho
3,337 satisfied customers
2008 Chevy Tahoe: owners manual..circuits..the trailer wire harness
I have a 2008 Chevy Tahoe. It says in the owners manual that the circuits for the trailer wire harness are installed but not hooked up. How can I connect this myself. Thanks… read more
Butch
Butch
Vocational, Technical or Trade Scho
290 satisfied customers
My 2000 Avalanche..annoying high pitched squeel..drivers side
My 2000 Avalanche has recently developed an annoying high pitched squeel in what seems to be the rear tire area on the driver's side. It is pretty constant going straight or curving to the right. It d… read more
supermechanic
supermechanic
Service consultant
Vocational, Technical or Trade Scho
10 satisfied customers
2009 GMC SIERRA DENALI: DEALER SAYS..BRAKE CONTROLLER..OLD ONES (
I HAVE 2009 GMC SIERRA DENALI 1/2T PICK UP WITH THE 6.2 LTR. MOTOR THE DEALER SAYS THE JL1 INTEGRATED BRAKE CONTROLLER HE DID NOT ORDER CANNOT BE ADDED. WHY NOT? GM WILL NOT EVEN SHIP THE PARTS UNLESS… read more
GM Tech (Cam)
GM Tech (Cam)
Chevy Technician
Vocational, Technical or Trade Scho
15,756 satisfied customers
2003 gmc sierra 1500: wiring diagram..the IP relay block..V6..pickup
Can Frank get me the wiring diagram of the IP relay block of my 2003 GMS Sierra 1500, V6 4.3 pickup (cheep model). Frank got me information on most of the electric brake hookup, but I need to trace th… read more
GM-Frank
GM-Frank
ASE Master Certified
37 years Automotive Repair Exp.
431 satisfied customers
2005 GMC Sierra 1500: brake lights..wiring harness..GM..the trailer
problem recently developed with trailer turn signals, brake lights after working fine for years. 2005 GMC Sierra 1500 with factory trailer hitch / wiring harness, Tekonsha prodigy brake controller thr… read more
GM Tech (Cam)
GM Tech (Cam)
Chevy Technician
Vocational, Technical or Trade Scho
15,756 satisfied customers
2007 Tahoe: 12V power for the 7 pin trailer aux circuit
How do I connect the trailer brake and 12V power for the 7 pin trailer aux circuit for my 2007 Tahoe? I thought I had purchased a trailer package.… read more
Dave Nova
Dave Nova
Chevrolet Technician
Associate Degree
7,092 satisfied customers
Tahoe: chev...trailer brake..that was in my 06..color code
i have a chev. tohoe 07 i am looking to hook up my trailer brake control but dont see the 4 plug hook up that was in my 06 chev. 1500 are the wires tape under the dash the wires for the hook up and if… read more
Bob
Bob
Vocational, Technical or Trade Scho
2,784 satisfied customers
I have a 2003 GMC Sierra 2500HD truck. I have no voltage ...
I have a 2003 GMC Sierra 2500HD truck. I have no voltage on the trailer towing package brake lights, all other lights and electric brake work fine. Suggestions… read more
Greg A.
Greg A.
Bachelor\u0027s Degree
37 satisfied customers
factory..7 pin trailer connector to the wire loom..master cylinder
I want to connect the battery power to the factory trailer power cable with out using a trailer brake controller. it is the red wire from the 7 pin trailer connector to the wire loom under the master … read more
Bob
Bob
Vocational, Technical or Trade Scho
2,784 satisfied customers
Where does the electric trailer brakes get its power from ...
Where does the electric trailer brakes get its power from when the truck brakes are applied on a 2007 Chev Silverado 2500 HD?… read more
goodwrench9124
goodwrench9124
Lead Tech/ Shop Leader
Vocational, Technical or Trade Scho
2,571 satisfied customers
2007 Silverado 1500: wiring harness..towing package..steering column
I have just bought a 2007 Silverado 1500 New Body style and would like to install a Prodigy 2.6 brake controller. I can't seem to find a wiring harness for this truck model. I have the towing package … read more
goodwrench9124
goodwrench9124
Lead Tech/ Shop Leader
Vocational, Technical or Trade Scho
2,571 satisfied customers
1500 Chevy: the trailer brake controller..GM..tow..wire harness
Where is the trailer brake controller receptical on a 2005 3500 Express van. This is a tekonsha Prodigy that I took out of my 1500 Chevy pickup and has the GM plug on it. The van was equiped with the … read more
Maven
Maven
Cadillac Technician
Vocational, Technical or Trade Scho
8 satisfied customers
MY 2000, Silverado,1500, Z71 emergency brakes wore down to ...
MY 2000, Silverado,1500, Z71 emergency brakes wore down to the metal even tho they were never used. My mechanic replaced them and also the rotors and the right rear wheel still runs "Hot" due to the e… read more
ttiger79
ttiger79
Auto Mechanic
High School or GED
880 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x