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This is for any member whom is interested in installing an aftermarket trailer hitch and Trailer Wiring Package on a 2007 GMC Acadia under Factory Warranty.

I spent almost 6 weeks reading post on this site and spent 3 weeks working with my local dealership in Atlanta Georgia. I have orders roughly $65 worth of parts :banghead:that do not work or wrong…..This post will provide you detailed instruction on having your dealership repair this Under Factory Warranty. If you are looking to piece fuses and fuse boxes along with wiring harness please be careful. I tried the same thing and got burned doing so. I ordered the incorrect parts that people on this forum said had worked for them. Not the case for me. All I wanted was a Trailer Hitch on the Acadia that would tow an 1,800lb boat with all functional lighting. This is what I have provided

I would first like to say that this site has been a great place to gather information about installing a trailer, but it has taken me over 6 weeks to gather the information and install a hitch and wiring on my GMC Acadia. I own a 2007 GMC Acadia SL model with out a factory installed towing package. With this being said below are the detailed instructions on what steps need to be taken to install a hitch, fuse box, fuse, GMC wiring harness, and T-one 7 to 4 trailer harness for GMC models.

Step One- Make sure your Acadia was manufactured and built before July 2, 2007 in order to have this performed under factory warranty at your local dealership. To find this information you can contact your dealer with your vin number.

Step Two- Here is a list of parts you will need to complete the install:
1- Underhood Bussed Electrical Center – Dealership & Covered under Warranty
2- Bussed Electrical Fuse – Dealership & Covered under Warranty
3- GMC Factory Acaida Wiring Harness / this part will allow you to use the standard 7 plug GMC harness- Dealership Covered under Warranty
4- T-one connector for GMC Acadia – This harness plugs into the 7 plug GMC harness and converts it to a 4 plug- $40.65 from usa-traiers.com * free shipping http://www.usa-trailer-hitches.com/products/118384
5- Round Tube Max-Frame receiver hitch – This is the actual metal hitch that bolts to the under part of your Acadia - $117.95 from usa-trailer.com * free shipping http://www.usa-trailer-hitches.com/products/Round_Tube_Max_Frame_Receiver,75528
6- Ball mount kit w/ Pin - $22.95 * free shipping http://www.usa-trailer-hitches.com/products/2923
7- Zinc Hitch Ball -$9.95 * free shipping http://www.usa-trailer-hitches.com/products/63833

Step Three- Print this TSB and Go to Dealership and provide this Service Bulletin to them so they understand you know that this is covered under Factory Warranty:

Subject: Supplemental Information on Recreational Vehicle and Trailer Towing and Trailer Wiring Accommodation for Non-V92 Equipped Vehicles #07-00-89-021A - (06/27/2007)

Models: 2008 Buick Enclave

2007 GMC Acadia

2007 Saturn OUTLOOK

This bulletin is being revised to add models and revise dinghy towing procedures. Please discard Corporate Bulletin Number 07-00-89-021 (Section 00 - General Information).

The purpose of this bulletin is to inform dealers of special procedures necessary when towing a trailer or when towing the vehicle behind a recreational vehicle.
Towing a Trailer

Trailer Weight Information
The following chart shows how much the trailer can weigh, based on the vehicle powertrain combination. Retailers should refer customers to the appropriate Owner Manual for important trailering tips, vehicle maintenance, and safety rules before towing a trailer.
Vehicle Maximum Trailer Weight
3.6L V6 (LY7) Engine with Front-Wheel Drive and 6-Speed Automatic Transaxle (MY9) with Trailer Provisions (V92) 4,500 lb. (2,041 kg)
3.6L V6 (LY7) Engine with Front-Wheel Drive and 6-Speed Automatic Transaxle (MY9), NO Trailer Provisions 2,000 lb. (907 kg)
3.6L V6 (LY7) Engine with All-Wheel Drive and 6-Speed Automatic Transaxle (MH6) with Trailer Provisions (V92) 4,500 lbs. (2,041 kg)
3.6L V6 (LY7) Engine with All-Wheel Drive and 6-Speed Automatic Transaxle (MH6), NO Trailer Provisions 2,000 lb. (907 kg)

Towing a Trailer with a Vehicle NOT Equipped with Trailer Provisions
2008 Buick Enclave, 2007 GMC Acadia and 2007 Saturn OUTLOOK vehicles that are not equipped with trailer provisions (RPO V92) must be modified with a new underhood bussed electrical center (UBEC) to provide full functionality for 4 circuits: ground, tail lamps, RH and LH stop/turn lamps. Refer to the Parts Information section in this bulletin for the correct part numbers. To find the original part number, remove the UBEC and look at the side of the UBEC.
This UBEC replacement should only be performed for customers who perform trailer towing. UBEC replacement for trailer towing is only covered under warranty for 2007 model year GMC Acadia and Saturn OUTLOOK vehicles, and 2008 Buick Enclave vehicles.

Towing a Trailer with a Vehicle with Trailer Provisions (RPO V92)
The following procedure may need to be performed to the backup lamp circuit. Perform this procedure only if the customer will be using the vehicle to tow.
1. Disconnect the X7 connector from the Body Control Module (BCM).
2. Remove the terminal for pin 3 from the BCM X7 connector. The wire to this terminal is dark blue and is the 38 circuit.
3. Re-connect the X7 connector to the BCM.
4. Cut the terminal off the end of this wire and strip the end of the wire.
5. Splice this wire into the 24 circuit wire that goes into BCM connector X6, pin 2. The 24 circuit is light green.
Recreational Vehicle Towing (Dinghy Towing)

Important: To avoid battery rundown while towing, remove the 50 amp BATT1 fuse in the UBEC. Refer to the dinghy towing procedure in this bulletin.
Recreational Vehicle Towing Information
Important: Vehicles with a 6-speed automatic transmission that are "dinghy towed" must be started at the beginning of each day and at each fuel stop for a minimum of five minutes.

Recreational vehicle towing means towing the vehicle behind another vehicle -- such as behind a motorhome. The two most common types of recreational vehicle towing are known as "dinghy towing" (towing the vehicle with all four wheels on the ground) and "dolly towing" (towing the vehicle with two wheels on the ground and two wheels up on a device known as a "dolly"). With the proper preparation and equipment, many vehicles can be towed in these ways. Refer to the appropriate model/model year Owner Manual for towing preparation guidelines and dolly and dinghy towing procedures. The Towing Chart below summarizes powertrain combination compatibility with dolly and dinghy towing methods.
2008 Buick Enclave, 2007 GMC Acadia, 2007 Saturn OUTLOOK Recreational Vehicle Towing Chart

Powertrain Combination and Towing Method Rear Wheels on a Tow Dolly Front Wheels on a Tow Dolly All Four Wheels on the Ground (Dinghy)
3.6L V6 (LY7) Engine with Front-Wheel Drive and 6T75 Six-Speed Automatic Transaxle (MY9) No Yes Yes*
3.6L V6 (LY7) Engine with All-Wheel Drive and 6T75 Six-Speed Automatic Transaxle (MH6) No No Yes*
*Notice: If the vehicle is equipped with a 6T75 six-speed automatic transmission, it can be dinghy towed from the front for unlimited miles at 65 mph (105 km/h). To avoid vehicle damage, never exceed 65 mph (105 km/h) while towing Buick Enclave, GMC Acadia and Saturn OUTLOOK vehicles. The repairs would not be covered by the warranty.

Dinghy Towing Procedure
Notice: If you tow your vehicle without performing each of the steps listed under "Dinghy Towing," you could damage the automatic transmission. Be sure to follow all steps of the dinghy towing procedure prior to and after towing your vehicle.
Notice: Don't tow a vehicle with the front drive wheels on the ground if one of the front tires is a compact spare tire. Towing with two different tire sizes on the front of the vehicle can cause severe damage to the transmission.
Important: Buick Enclave, GMC Acadia and Saturn OUTLOOK vehicles may only be dinghy towed from the front, with all four wheels on the ground.
1. Position the vehicle to tow and then secure it.
2. Shift transmission to PARK (P) and turn the ignition to OFF.
3. Set the parking brake.
4. Turn the ignition to ACCESSORY.
5. Shift your transmission to NEUTRAL (N).
6. To prevent your battery from draining while the vehicle is being towed, remove the 50 amp BATT1 fuse in the UBEC, and store in a safe location.
7. Release the parking brake.
Once you have reached your destination, do the following steps:
1. Set the parking brake.
2. Reinstall the BATT1 fuse.
3. Shift the transmission to PARK (P), turn the ignition key to OFF and remove the key from the ignition.
4. Release the parking brake.
Parts Information

Part Number Description
25784721 Underhood Bussed Electrical Center
(replaces 25784722)
25784723 Underhood Bussed Electrical Center
(replaces 25784726)
25784725 Underhood Bussed Electrical Center (replaces 25784724)
Warranty Information

For vehicles repaired under warranty, use:
Labor Operation Description Labor Time
N1730 Block Assembly, Wiring Harness Junction - Engine - Replace 0.3 hr

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.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright General Motors Corporation. All Rights Reserved.

Step Four- You dealership should provide you any feedback on the Fuse Block, Fuse, and factory wiring 7 pin wiring harness. Once all repairs are complete be sure to test both the 7-pin connector and if applicable the 4 pin T-one connector harness.

This is it- you should have completed the install and you are all set to go….. :cheers:
 

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Re: [b]This is for any member whom is interested in installing an aftermarket traile

I find it so hard to understand why there are dealer that know about this issue and others have no idea or have never heard of this problem. After talking to 3 dealers and having an 08 (that they won't do under warranty) I did my own setup. Now if I can make this work and it wasn't very hard then these dealers should be able to setup these Acadia's Outlooks and Enclaves too! :banghead:
 

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Re: [b]This is for any member whom is interested in installing an aftermarket traile

Its fairly simple, this car is going into its 3rd year of production. Most people that buy these cars without the towing package dont want or need it. For the few of us that actually do want to add it we have to find out the hard way that it is not as easy as it has been on past GM vehicles. The dealers dont know this either becuase unfortunately the training for these dealers sucks. It would be nice for GM to have a more in-depth training program for the sales staff and the service staff so the people selling and working on theses vehicles were better educated. But they are more concerned about selling volume than making sure their people are as knowledgeable as they should be. Some dealers are better about getting their people educated and some dont care about anything but selling the vehicles.
 

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Re: [b]This is for any member whom is interested in installing an aftermarket tr

So here's my "maybe I just missed it" question ...

With an '08 Acadia, why isn't the UBEC replacement covered under factory warranty? Is it because I already have the circuits I need, or is it because they want to $queeze a few dollars out of me for not ordering the towing package up front?
 

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Re: [b]This is for any member whom is interested in installing an aftermarket tr

dmurphy said:
So here's my "maybe I just missed it" question ...

With an '08 Acadia, why isn't the UBEC replacement covered under factory warranty? Is it because I already have the circuits I need, or is it because they want to $queeze a few dollars out of me for not ordering the towing package up front?
$queeeze!!!
 

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Re: [b]This is for any member whom is interested in installing an aftermarket tr

GAR said:
dmurphy said:
So here's my "maybe I just missed it" question ...

With an '08 Acadia, why isn't the UBEC replacement covered under factory warranty? Is it because I already have the circuits I need, or is it because they want to $queeze a few dollars out of me for not ordering the towing package up front?
$queeeze!!!
I can see the squeeze play but why do they include the 08 Enclave? Or is it the fact that not as many of them would ever pull a trailer? Not that I am saying that they are to good for that but the Enclave is more for the people who don't need or want to pull a trailer
 

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Re: [b]This is for any member whom is interested in installing an aftermarket traile

I think it had to do with the timing of what was printed in the owner's manuals. (but I could be wrong). If my memory is correct, they changed the wording in the manuals so that it no longer implied that it was under warranty. I think the Buick's manuals just got changed later. That's my opinion. :)
 

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Discussion Starter · #8 ·
Re: [b]This is for any member whom is interested in installing an aftermarket traile

This is CORRECT!!!! The manual was corrected for 08' Acadia's, Outlook's and Enclave's. If you have one of these models sorry. It might set you back as much as $500 to instal the aftermarket hitch. ie Get them with the tow package before you buy. I hope this has helped others like me. I can tell you how many forums I have been to trying to figure this mess out. If anyone has any other questions please let me know. :thumb:
 

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Re: [b]This is for any member whom is interested in installing an aftermarket traile

Ok, so I'm a little slow I take it. Also, I realize this thread is quite old, but we just took our 07 SLE in for the TSB on the fuse block. They had it done in 2 hours. Picked it up and promptly tested for power at the rear harness (round plug with 4 wires) under the bumper. Nothing. Am I missing something or is the dealership missing something!? I thought that I'd have power at the plug for turn, brake, lights. What gives? Help!
 

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Re: [b]This is for any member whom is interested in installing an aftermarket tr

matstang said:
Ok, so I'm a little slow I take it. Also, I realize this thread is quite old, but we just took our 07 SLE in for the TSB on the fuse block. They had it done in 2 hours. Picked it up and promptly tested for power at the rear harness (round plug with 4 wires) under the bumper. Nothing. Am I missing something or is the dealership missing something!? I thought that I'd have power at the plug for turn, brake, lights. What gives? Help!
Even though they change the fuse block, you still need to replace the rear wiring harness that runs from the right wheel well to the hitch area. At least that's what I had to do on my 07 SLT. The only thing I haven't done so far is move the back up light wire at the BCM, but I'm not too concerned with that right now since I don't plan on using it.
 

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So then that harness is not part of the bulletin? It sounds like power is only supplied then to the rr wheel well area until you install the correct harness from the wheel well to the rear bumper area? GM has not impressed me in this area at all...it's hard going from a Honda to a GMC!
 

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I have the V92 option and although I won't tow much; I like the idea that I will be able to hook up and go. It seems that GM has a lot of variables involved with vehicles that don't have this option. I think GM could have made this option easier to install aftermarket
 

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jsimms said:
I have the V92 option and although I won't tow much; I like the idea that I will be able to hook up and go. It seems that GM has a lot of variables involved with vehicles that don't have this option. I think GM could have made this option easier to install aftermarket
i agree. as some have probably noticed i am trying to get a hitch put on my 2009. I have already had a couple conversations with my dealership salesman about it, and i have found either ...

A) the 2009 is better equipped to handle an aftermarket job regarding fuses/wiring etc., or

B) my salesman is blowing smoke, doesn't really know what the crap he's talking about, and is going to have to spend more money than he planned to get the job done, or

C) my salesman is well aware of what's needed, and it can be done for the cost of hitch plus about $150.

I'm guessing B at this point. But, even after i told him i had concerns about it from reading on the forum, he said "yes you will have all the necessary wiring done that is why i set aside $300 allowance for the hitch instead of $100-200." So, maybe he's "in the know". He claimed he could get the hitch alone for a little over a $100 through Uhaul, but after i stressed to him i wanted the cover plate to fit properly he said he would make sure that it would work first but that we might just have to do the GM factory hitch. (he insists that I will get a better hitch, class III, with better warranty coverage at Uhaul...)
 

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Since most of the hitch problems and threads have been about 2007 and 2008's i will definitely post soon in the next week or so how this all worked out. Correct me if I'm wrong, but i don't think I've specifically seen a poster with a 2009 comment on getting a hitch installed. Maybe GM decided to equip them better after having the TSB on 2007's and complaints about the process and availability issues on 2008's.

This is seriously ridiculous. My 1995 Ford Ranger only required a $30 wiring harness and about 15mins of labor for me to install trailer lights on it way back when. In fact every vehicle i've ever owned simply had to have a harness "plugged" in basically to the wiring running to the tailights.. and 'ouaLaa, trailering lights were ready.
 

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jiggly said:
Since most of the hitch problems and threads have been about 2007 and 2008's i will definitely post soon in the next week or so how this all worked out. Correct me if I'm wrong, but i don't think I've specifically seen a poster with a 2009 comment on getting a hitch installed. Maybe GM decided to equip them better after having the TSB on 2007's and complaints about the process and availability issues on 2008's.

This is seriously ridiculous. My 1995 Ford Ranger only required a $30 wiring harness and about 15mins of labor for me to install trailer lights on it way back when. In fact every vehicle i've ever owned simply had to have a harness "plugged" in basically to the wiring running to the tailights.. and 'ouaLaa, trailering lights were ready.
You may be right
 

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jiggly said:
This is seriously ridiculous. My 1995 Ford Ranger only required a $30 wiring harness and about 15mins of labor for me to install trailer lights on it way back when. In fact every vehicle i've ever owned simply had to have a harness "plugged" in basically to the wiring running to the tailights.. and 'ouaLaa, trailering lights were ready.
You are definitely right about this. Being a mechanic, I too have done many trailer light hook-ups and have never seen something as complicated as this. I understand that LED's come with a price, but this is not acceptable. There was no 'thinking ahead' when GM developed this one... I cannot understand why it has to be such a run-around to do this! I've found the biggest problem is that I have to tell my dealer how to do the fix! The only way I'm learning about it is through this forum!

So, the question remains...do I need to purchase the harness from the rr wheel well area? Sounds like I better check for power to the rr wheel area. I will post back when I know. Thanks for all the responses.
 

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matstang said:
You are definitely right about this. Being a mechanic, I too have done many trailer light hook-ups and have never seen something as complicated as this. I understand that LED's come with a price, but this is not acceptable. There was no 'thinking ahead' when GM developed this one... I cannot understand why it has to be such a run-around to do this! I've found the biggest problem is that I have to tell my dealer how to do the fix! The only way I'm learning about it is through this forum!

So, the question remains...do I need to purchase the harness from the rr wheel well area? Sounds like I better check for power to the rr wheel area. I will post back when I know. Thanks for all the responses.
I agree, GM really missed the boat on this setup. Seems to me they could have just used 1 fuse box and all the wiring to the rear. Then just plug into it as my 97 GMC is, put a hitch and brake controller on it (if desired) and go.
What I found on mine is all the wiring from the fuse box to the right rear wheelwell is there. It's just necessary to replace the fuse box with the proper one and then swap out the harness along the rear of the vehicle with the one that has all the wiring in it. I couldn't talk my dealer into replacing the fuse box under warranty but at least I got it at their cost, so now I have plenty of spare fuses and relays, just in case.
I made the mistake when I ordered mine of not verifying it came with the tow package. I had looked at 2 other Acadias on the lot and they both had hitches on them, so I just assumed it came standard (my mistake for assuming) like my 02 Olds Bravada did. We didn't care for the colors of the ones they had so we ordered ours and they didn't even mention the tow package. I definitely won't make that mistake again.
 

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Re: [b]This is for any member whom is interested in installing an aftermarket traile

matstang said:
Ok, so I'm a little slow I take it. Also, I realize this thread is quite old, but we just took our 07 SLE in for the TSB on the fuse block. They had it done in 2 hours. Picked it up and promptly tested for power at the rear harness (round plug with 4 wires) under the bumper. Nothing. Am I missing something or is the dealership missing something!? I thought that I'd have power at the plug for turn, brake, lights. What gives? Help!
So, I thought I'd get back to the forum and let all know what I found out. This is what I found out: I AM a little slow. I was using a bad ground when testing for power at the harness in the bumper. Yes, I am slow. Make sure you've got a good ground to check for power...yeah, rule #1 when doing anything electrical... :-[
One more question though...do I really have to buy the 7 pin to flat 4 connector? Is there any reason I can't just solder in a flat 4 after cutting off the 7 pin connector? (The 7 pin really only has 4 wires going to it.) What would it hurt?
 

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Re: [b]This is for any member whom is interested in installing an aftermarket traile

matstang said:
do I really have to buy the 7 pin to flat 4 connector? Is there any reason I can't just solder in a flat 4 after cutting off the 7 pin connector? (The 7 pin really only has 4 wires going to it.) What would it hurt?
I think that will find that the 7 pin connector will out last the flat 4. The 7 is far more durable, if it was me it there would be no question about gettting the 7 to 4.
 

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Re: [b]This is for any member whom is interested in installing an aftermarket traile

toyjunkie said:
I think that will find that the 7 pin connector will out last the flat 4. The 7 is far more durable, if it was me it there would be no question about gettting the 7 to 4.
I don't need/want a 7 pin connector. I have a trailer that has a flat 4 and that's all I will be towing. Anyone know if it matters that I cut the 7 pin factory connector off and solder on a flat 4? Seems like a pretty simple thing to do, just wondering if I'm going to screw anything up!? Anyone already screwed their Acadia up before I do it to mine? ;)
 
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