Do I Have Factory Tow Package?

vskidmoreII · November 18, 2007

I just bought a 2003 Yukon XL, 5.3L 4x4, 1/2 ton. I am trying to determine if I have a factory tow package. It does have a receiver hitch and 7 pin trailer harness but I do believe these have been added on. I don't see a tranny cooler in front of the radiator. I am looking for the plug to connect a brake controller.

Any advise or codes I need to look for? There is a sticker in the glove box with a bunch of codes on it.

Thanks for the help.

hoorders · November 23, 2007

If you do not have Z82 then you do not have the factory towing package.
You can still add an electric brake controller though,You just have to buy the jumper harness from your GM dealer,Its GM part number 15085418 and lists for around $26.00,It will plug in under the dash on the left hand side (By the footwell "A-pillar" panel/E-brake pedal) theres a black plastic cover which covers where it plugs into,remove the cover and plug it in and just run the wires up and splice them into your controller.

Oh and don't forget to install the fuse in the underhood electrical center,They give one with the jumper harness so you shouldn't forget.

Perfect, just what I need to know

Thanks again.....

My 2000 silvy also does not have the factory tow package......when I plugged my brake controller into the correct plug under the dash.....it did not power up.....I also installed the 40amp fuse under the dash and still no power to the controller......I thiink if your truck did not come with the factory tow package, then the plug under the dash will not work.

Let me know if you are successfull at powering your controller from the factory location under the dash......thanks.

make sure you have the right controller harness for your model year truck. if i remember when i hooked mine up in my 03 i had a 01 harness that i used, and the controller did not work. gm made a change in the wiring so some harness will not interchange from one year to another

I bought the 99-02 harness for my 2000.......still no juice to the controller...............checked the plug where the harness goes to with my test light and there is no power there........thats why im 'assuming' if the vehicle did not come with the factory tow package......then that plug is not wired..........would love to get a definitive answer to that though or maybe im missing something...

pastorscott · November 29, 2007

Hey

I have the factory tranny cooler and its pretty cheaply. I would like to see how hard it is to upgrade and change out. Lets see those pictures

thanks

Scott

hoorders · November 22, 2007

If you do not have Z82 then you do not have the factory towing package.
You can still add an electric brake controller though,You just have to buy the jumper harness from your GM dealer,Its GM part number 15085418 and lists for around $26.00,It will plug in under the dash on the left hand side (By the footwell "A-pillar" panel/E-brake pedal) theres a black plastic cover which covers where it plugs into,remove the cover and plug it in and just run the wires up and splice them into your controller.

Oh and don't forget to install the fuse in the underhood electrical center,They give one with the jumper harness so you shouldn't forget.

Perfect, just what I need to know

Thanks again.....

My 2000 silvy also does not have the factory tow package......when I plugged my brake controller into the correct plug under the dash.....it did not power up.....I also installed the 40amp fuse under the dash and still no power to the controller......I thiink if your truck did not come with the factory tow package, then the plug under the dash will not work.

Let me know if you are successfull at powering your controller from the factory location under the dash......thanks.

silverad03 · November 18, 2007

I think Z82 is the factory towing package, but the Z82 RPO may just refer to a suspension package only.

BigJayDogg3 · November 18, 2007

Look in the glovebox for the codes. If I remember correctly that is where they were that year. Unless they moved from the door to the glovebox then back to the door.

desrtrat · November 23, 2007

If you do not have Z82 then you do not have the factory towing package.
You can still add an electric brake controller though,You just have to buy the jumper harness from your GM dealer,Its GM part number 15085418 and lists for around $26.00,It will plug in under the dash on the left hand side (By the footwell "A-pillar" panel/E-brake pedal) theres a black plastic cover which covers where it plugs into,remove the cover and plug it in and just run the wires up and splice them into your controller.

Oh and don't forget to install the fuse in the underhood electrical center,They give one with the jumper harness so you shouldn't forget.

Perfect, just what I need to know

Thanks again.....

My 2000 silvy also does not have the factory tow package......when I plugged my brake controller into the correct plug under the dash.....it did not power up.....I also installed the 40amp fuse under the dash and still no power to the controller......I thiink if your truck did not come with the factory tow package, then the plug under the dash will not work.

Let me know if you are successfull at powering your controller from the factory location under the dash......thanks.

make sure you have the right controller harness for your model year truck. if i remember when i hooked mine up in my 03 i had a 01 harness that i used, and the controller did not work. gm made a change in the wiring so some harness will not interchange from one year to another

BurroWDMS · November 29, 2007

Wow! Thanks for the info!!!!

akinz · February 10, 2009

If you do not have Z82 then you do not have the factory towing package.
You can still add an electric brake controller though,You just have to buy the jumper harness from your GM dealer,Its GM part number 15085418 and lists for around $26.00,It will plug in under the dash on the left hand side (By the footwell "A-pillar" panel/E-brake pedal) theres a black plastic cover which covers where it plugs into,remove the cover and plug it in and just run the wires up and splice them into your controller.

Oh and don't forget to install the fuse in the underhood electrical center,They give one with the jumper harness so you shouldn't forget.

Perfect, just what I need to know

Thanks again.....

My 2000 silvy also does not have the factory tow package......when I plugged my brake controller into the correct plug under the dash.....it did not power up.....I also installed the 40amp fuse under the dash and still no power to the controller......I thiink if your truck did not come with the factory tow package, then the plug under the dash will not work.

Let me know if you are successfull at powering your controller from the factory location under the dash......thanks.

make sure you have the right controller harness for your model year truck. if i remember when i hooked mine up in my 03 i had a 01 harness that i used, and the controller did not work. gm made a change in the wiring so some harness will not interchange from one year to another

I bought the 99-02 harness for my 2000.......still no juice to the controller...............checked the plug where the harness goes to with my test light and there is no power there........thats why im 'assuming' if the vehicle did not come with the factory tow package......then that plug is not wired..........would love to get a definitive answer to that though or maybe im missing something...

I was wondering the same thing for my 2000 sierra. From what I've found out myself and from research, if you look underneath your truck and locate the wiring harness for your trailer, there are one of two things you will see:

6 wires - white, green, brown, yellow, light green and light blue === NO TRAILER TOW PACKAGE

7 wires - I beleive the same as above but with the addition of a power wire, most likely red. ==== TRAILER TOW PACKAGE

I found this out cause when I bought my truck, it had no trailer hitch. The last sierra I owned which had the Z71 package had the OEM hitch and wiring.

I got an OEM hitch at an auto recyclers along with the plug and some wire( the guy just cut the harness off) When I got around to wiring up my plug, everything went perfectly fine, just followed the colour code and left the red from the plug disconnected since it was the 7th wire I didn't have... again signs of no tow package.

So I checked all my lights with a light and all signals, brake lights tail lights worked perfectly. I went to pick up my dad's motorcycle trailer and when I connected it, I noticed that the brakes came on everytime I pushed the brake pedal. It was violent to say the least. So then I start thinking well I don't know why my other truck didn't do this. I couldn't understand how the electric brake circuit could be prewired for something like that without a controller.

I ended up ordering a controller which was today and tonight I began just doing a little pre-work for the controller. I kept the pigtail harness that my last sierra came with (Which was also a 2000) and plugged the fuse in Stud #1 of the UnderHood electrical center. By looking at the schematic on the pigtail, it looked like I should have 12V supplied from the fuse I just put in to the relay box that is by the parking brake.

I had no power. I had ground, I had power when I pushed the brake pedal but I didn't have a constant 12V.

I pulled the relay box out and checked for votage on the wire itself, still no voltage.

I had voltage on both sides of the fuse so I proceeded to take the plastic cover off the UnderHood Electrical center and found that there was a blue and red wire that were not connected to anything.

The red wire had a ring type fastener crimped on the end and the blue wire has a connector.

I pulled the connecter out that went in the area that my 40 fuse was and there was only 1 wire connected to it. On the side of the connector there were markings A and B. A and B being the locations of the wire. A was occupied by a red power wire and B was vacant.

I put a jumper on the ring terminal of the red wire I found disconnected and placed the other end of the jumper in a fuse block. I checked for voltage at my relay box and found my voltage. Did the same for the blue wire.

At this point I new that placing a brake controller wouldn't be a simple plug and play installation as assumed...

Because I didn't have the factory tow package. None of these wires are hooked up. I have no clue what the blue wire should be connected to, all I know is that it show's its for the brake output on the brake controller.

And by reading through the problem you had before with the CHMSL not working... Well first of all I was like the other guy and had no friggan clue what it stood for but then I realized that I spliced into that wire with the electric brake wire of the plug when I installed my plug....

So.. everytime I was hitting the brakes it was sending 12V from the brake switch to the electric brakes on the trailer and giving them full juice...

Man what a novel... don't blame anyone for not reading this I was just so happy to figure out that I didn't have a trailer package and also found out my electric brake problem... I'll just have to drive down to FL without trailer brakes like I always have... On my next truck though... I'm going to make sure it's got the factory tow package!!!

LAter!

PHEW!!

vskidmoreII · November 18, 2007

Look in the glovebox for the codes. If I remember correctly that is where they were that year. Unless they moved from the door to the glovebox then back to the door.

Thanks guys. The codes are in the glove box and I do not find Z82 code.

Next question: Does that mean I cannot wire in a controller?

MS3DALE · November 18, 2007

If you do not have Z82 then you do not have the factory towing package.

You can still add an electric brake controller though,You just have to buy the jumper harness from your GM dealer,Its GM part number 15085418 and lists for around $26.00,It will plug in under the dash on the left hand side (By the footwell "A-pillar" panel/E-brake pedal) theres a black plastic cover which covers where it plugs into,remove the cover and plug it in and just run the wires up and splice them into your controller.

Oh and don't forget to install the fuse in the underhood electrical center,They give one with the jumper harness so you shouldn't forget.

MS3DALE · November 18, 2007

I think Z82 is the factory towing package, but the Z82 RPO may just refer to a suspension package only.

Your right,Z82 is the factory towing package.It has nothing to do with the suspension package,your thinking of Z85 which is the heavy-duty suspension package.

vskidmoreII · November 18, 2007

If you do not have Z82 then you do not have the factory towing package.
You can still add an electric brake controller though,You just have to buy the jumper harness from your GM dealer,Its GM part number 15085418 and lists for around $26.00,It will plug in under the dash on the left hand side (By the footwell "A-pillar" panel/E-brake pedal) theres a black plastic cover which covers where it plugs into,remove the cover and plug it in and just run the wires up and splice them into your controller.

Oh and don't forget to install the fuse in the underhood electrical center,They give one with the jumper harness so you shouldn't forget.

Perfect, just what I need to know

Thanks again.....

C & A s Dad · November 18, 2007

Verle, if you are planning to do any towing, I would suggest you add an aux trans cooler. Be sure and get a good stacked plate cooler and not a tube and fin design.

If you get ready to do this, PM me with an e mail address and I can send you some really detailed pics of mine installed on my 02 Yuk XL. It is an easy job because you can remove the grill assy in about 5 mins. Then you can get to everything very easy.

BurroWDMS · November 28, 2007

If you do not have Z82 then you do not have the factory towing package.
You can still add an electric brake controller though,You just have to buy the jumper harness from your GM dealer,Its GM part number 15085418 and lists for around $26.00,It will plug in under the dash on the left hand side (By the footwell "A-pillar" panel/E-brake pedal) theres a black plastic cover which covers where it plugs into,remove the cover and plug it in and just run the wires up and splice them into your controller.

Oh and don't forget to install the fuse in the underhood electrical center,They give one with the jumper harness so you shouldn't forget.

Does this apply to the new bodied trucks as well? I bought a '07 Sierra 1500 CC and it has the trans cooler & hitch but no brake controller. Will that part # you supplied work for my application as well?

Thanks for your help!

MS3DALE · November 28, 2007

If you do not have Z82 then you do not have the factory towing package.
You can still add an electric brake controller though,You just have to buy the jumper harness from your GM dealer,Its GM part number 15085418 and lists for around $26.00,It will plug in under the dash on the left hand side (By the footwell "A-pillar" panel/E-brake pedal) theres a black plastic cover which covers where it plugs into,remove the cover and plug it in and just run the wires up and splice them into your controller.

Oh and don't forget to install the fuse in the underhood electrical center,They give one with the jumper harness so you shouldn't forget.

Does this apply to the new bodied trucks as well? I bought a '07 Sierra 1500 CC and it has the trans cooler & hitch but no brake controller. Will that part # you supplied work for my application as well?

Thanks for your help!

Actually you don't need anything,The wiring is already under the dash on the GMT900 trucks for adding a brake controller.

Heres a bulletin from GM on it (It has pictures but they wouldn't copy and paste over for me)......

Document ID# 2014482

Subject: Information on Auxiliary Power Wire at Trailer and Installation of Aftermarket Trailer Brake Controller - Towing, Tow #06-08-45-008A - (09/18/2007)

Models: 2007-2008 Cadillac Escalade, Escalade ESV, Escalade EXT

2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007-2008 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

Important: Installation of an electric brake controller and the wiring connections outlined in this bulletin are the responsibility of the dealership or customer. These repairs should never be charged to warranty. If you have any questions, please consult with your District Service Manager.

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.

An aftermarket brake controller will need to be installed/connected to the blunt wires under the left side of the IP for vehicles built without JL1 - Integrated Brake Controller. The following steps should be used to complete the installation.

Locate the trailer brake control circuits that are looped and taped to the main harness under the instrument panel.

Pull the trailering wire harness down.

Match the vehicle harness label circuit functions to the trailer brake controller jumper harness functions.

Important: The color or wires to be joined together may not match.

• Dark Blue Wire: switched power from controller to trailer brakes

• Red with Black Stripe: fused vehicle power to electrical brake controller

• Light Blue with White Stripe: Brake switch input to power electric brake controller

• White: ground

• Orange: CHMSL (Center High Mounted Stop Lamp) -- not required with most systems

After completing the under dash connections to the electric brake controller, open the hood and locate the red wire that is taped to the harness between the underhood electrical center and the driver side front fender.

Break the tape on the red/black wire and pull it toward the front of vehicle.

Remove the lid from the electrical center.

Place the terminal on the larger of the two studs at the front of the electrical center and secure with an M8 nut. This is circuit #242 to stud #2, to power the aftermarket trailer brake controller.

Important: The fuse is already present in the vehicle to power the electrical trailer brake controller system.

AUXILIARY POWER: Circuit #742 for Auxiliary Power at the 7-way trailer connector is no longer connected by the GM Assembly Plant. If the customer desires auxiliary power at the trailer connector location (i.e. refrigeration, battery charger or interior light in the trailer), complete steps 8.1 thru 8.4 to connect circuit #742:

1. Locate the red/black wire, looped and taped to the chassis harness, below the brake master cylinder.

2. Break the tape and route the wire to the front of the underhood electrical center.

3. Place the terminal on the smaller of the two studs on the electrical center and secure with an M6 fastener. This is circuit #742 to stud #1 for auxiliary power to the 7-way trailer connector.

4. ONLY for vehicles without RPO TP2 - Auxiliary Battery, install a 40 amp fuse to power the circuit.

Important: For vehicles equipped with RPO TP2 -- Devices powered by this fuse will drain the vehicle battery if left connected with the vehicle not running.

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.

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