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Discussion Starter · #1 ·
I have seen several different towing/trailer harness problems.
I have an 2008 Acadia with tow package. I am trying to pull power from the light green reverse wire in the harness and I am getting no power. The manual says that if the reverse lights in the trailer connection aren't working contact the dealer.
Anyone else having this problem? and did you fix it yourself, or go through the dealer?
 

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Discussion Starter · #3 ·
I read that thread, but it seemed those were with 07's, so this was not fixed with the 08's?
WTF amazing!
 

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bonk1313 said:
I read that thread, but it seemed those were with 07's, so this was not fixed with the 08's?
WTF amazing!
ordered mine with the trailering package too and i was hoping they had fixed this one for the 08.... :angryfire: :uzi: GM Engineers!!!
 

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This information applies to the 2007 Saturn Outlook and GMC Acadia. Details will be covered in an upcoming bulletin. Here are highlights.

Towing with Vehicles without Trailer Provisions (RPO V92)

These vehicles can tow a maximum trailer weight of 2,000 lb. (907 kg).

These vehicles must be modified by installing a new underhood bussed electrical center (UBEC) to provide full functionality for 4 circuits: ground, tail lamps, RH and LH stop/turn lamps.

Underhood Bussed Electrical Center

Replacement UBEC
Original UBEC

25784721
25784722

25784723
25784726

25784725
25784724


To find the original part number, remove the UBEC and look at the side of the UBEC.

TIP: This UBEC replacement should be performed only for customers who perform trailer towing.

Towing with Vehicles with Trailer Provisions (RPO V92)

These vehicles can tow a maximum trailer weight of 4,500 lb. (2,041 kg) (fig. 17).



It is necessary to modify the wiring harness at the Body Control Module (BCM).

Disconnect the X7 connector from the BCM and remove terminal pin 3 (dark blue wire, 38 circuit). Re-connect the X7 connector.

Splice this wire into the wire at BCM connector X6, pin 2 (light green wire, 24 circuit).

Recreational Vehicle Towing (Dinghy Towing)

Recreational vehicle towing means towing the vehicle behind another vehicle, such as behind a motorhome.

Dinghy towing -- towing the vehicle with all four wheels on the ground

Dolly towing -- towing the vehicle with two wheels on the ground and two wheels on a dolly

TIP: To avoid battery rundown while towing, disconnect the battery before towing.

TIP: Vehicles with a 6-speed automatic transmission that are dinghy towed must be started and run for a minimum of five minutes at the beginning of each day and at each fuel stop.

Powertrain
Rear Wheels on Dolly
Front Wheels on Dolly
All Four Wheels on Ground
(Dinghy)

3.6L V6 (LY7) Engine
Front-Wheel Drive
6T75 Six-Speed Automatic Transaxle (MY9)
No
Yes
Yes*

3.6L V6 (LY7) Engine
All-Wheel Drive
6T75 Six-Speed Automatic Transaxle (MH6)
No
No
Yes*


* Unlimited miles at 65 mph (105 km/h). To avoid vehicle damage, never exceed 65 mph (105 km/h). The repairs would not be covered by the warranty.

IMPORTANT: The owner must observe all procedural steps in the bulletin when dinghy towing.

Before starting, do the following steps:

- Secure to tow vehicle.

- Ignition OFF.

- Set parking brake.

- Ignition to ACCESSORY.

- Shift transmission to NEUTRAL (N).

- Disconnect negative battery cable. Release parking brake.

At destination, do the following steps

- Set parking brake.

- Reconnect negative battery cable.

- Ignition OFF

- Remove key from ignition.
 

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Discussion Starter · #6 ·
SLEsierra, I am confused by your posting.
My vehcile is a 2008, and was built by GMC with the trailering hitch and wiring. Why would I have to install anything?
 

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You dont need to install anything. This is common with all Gm vehicles including their pickups. Unless you get a vehicle that already has the trailer brake controller installed then there are two wires not hooked up in the 7 pin harness. The dealership will do it for you. Most people dont tow trailers requiring the back up wire or the trailer brake wire so I guess GM decided not to hook it up on any of their vehicles. Gotta love GM
 

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I have an 08 with the factory trailer package. I checked the 7 Pin connector on mine and everything seems to work just fine. I have only had it about a week and have not installed the trailer brake yet, so obviously, the blue wire for that is dead, but everything else was functioning just fine. The backup circuit is the light green that is the center pin on the connector. I have one utility trailer with surge brakes and an enclosed trailer that uses the electric brake controller so I need both to work. I plan to tow the heavier enclosed trailer mainly with my Tahoe so I have not taken the time to install a brake controller yet.
 

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Discussion Starter · #9 ·
Raistmaj said:
. The backup circuit is the light green that is the center pin on the connector.
Did you put a volt meter on the terminal or on the wire?
How about the fuse in the fuse block under the hood?
All are dead on my 08
 

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When I picked up the vehicle, I did a quick check of the pins with my Fluke. Since all the pins (exluding the blue of course) checked out, I didn't go any further than that, so no, I did not check the fuse block under the hood.  I brought the meter because of all the problems I read about here and it was not clear to me if the problem was fixed yet or not.  Also I hooked it up to the trailers the first weekend we had it and everything worked fine.  Without the reverse, I can't back the trailer with surge brakes up the driveway.  FYI, the build date on the door says 2/7/08.  The dealer reported that the vehicle was completed on 2/27/08.  What is your build date?  Maybe the fix was a rolling change during the model year.
 
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