Found this on another forum I frequent. Thought some here might be interested. We picked up our Enclave on monday.
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.
Part Number Description
25784721 Underhood Bussed Electrical Center
25784723 Underhood Bussed Electrical Center
25784725 Underhood Bussed Electrical Center (replaces 25784724)
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.
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