GM Service Manual Online
For 1990-2009 cars only

Caution: The driver can lose control when pulling a trailer if the correct equipment is not used or the vehicle is not driven properly. For example, if the trailer is too heavy, the brakes may not work well or even at all. The driver and passengers could be seriously injured. The vehicle may also be damaged; the resulting repairs would not be covered by the vehicle warranty. Pull a trailer only if all the steps in this section have been followed. Ask your dealer/retailer for advice and information about towing a trailer with the vehicle.

Notice: Pulling a trailer improperly can damage the vehicle and result in costly repairs not covered by the vehicle warranty. To pull a trailer correctly, follow the advice in this section and see your dealer/retailer for important information about towing a trailer with the vehicle.

To identify what the vehicle trailering capacity is for your vehicle, you should read the information in "Weight of the Trailer" that appears later in this section.

Trailering is different than just driving your vehicle by itself. Trailering means changes in handling, durability and fuel economy. Successful, safe trailering takes correct equipment, and it has to be used properly.

That's the reason for this part. In it are many time-tested, important trailering tips and safety rules. Many of these are important for your safety and that of your passengers. So please read this section carefully before you pull a trailer.

If You Do Decide To Pull A Trailer

If you do, here are some important points:

    • There are many different laws, including speed limit restrictions, having to do with trailering. Make sure your rig will be legal, not only where you live but also where you'll be driving. A good source for this information can be state or provincial police.
    • Consider using a sway control if your trailer will weigh 4,000 lbs. (1 816 kg) or less. You should always use a sway control if your trailer will weigh more than 4,000 lbs. (1 816 kg). You can ask a hitch dealer about sway controls.
    • Don't tow a trailer at all during the first 500 miles (800 km) your new vehicle is driven. Your engine, axle or other parts could be damaged.
    • Then, during the first 500 miles (800 km) that you tow a trailer, don't drive over 50 mph (80 km/h) and don't make starts at full throttle. This helps your engine and other parts of your vehicle wear in at the heavier loads.
    • With an automatic transmission, you can tow in DRIVE (D). You may want to shift the transmission to THIRD (3) or, if necessary, a lower gear selection if the transmission shifts too often (eg., under heavy loads and/or hilly conditions).

Three important considerations have to do with weight:

    • the weight of the trailer,
    • the weight of the trailer tongue
    • and the weight on your vehicle's tires.

Weight of the Trailer

How heavy can a trailer safely be?

It depends on how you plan to use your rig. For example, speed, altitude, road grades, outside temperature and how much your vehicle is used to pull a trailer are all important. And, it can also depend on any special equipment that you have on your vehicle.

Look in the following chart to find the maximum trailer weight for your vehicle.

Vehicle

Axle Ratio

Maximum Trailer Weight

GCWR

2WD

3.42

5,000 lbs.

(2 270 kg)

10,000 lbs.

(4 535 kg)

3.73

5,500 lbs.

(2 497 kg)

10,500 lbs.

(4 762 kg)

4.10

6,000 lbs.

(2 724 kg)

11,000 lbs.

(4 989 kg)

4WD

3.42

4,800 lbs.

(2 179 kg)

10,000 lbs.

(4 535 kg)

3.73

5,300 lbs.

(2 406 kg)

10,500 lbs.

(4 762 kg)

4.10

5,800 lbs.

(2 633 kg)

11,000 lbs.

(4 989 kg)

*The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversion. The GCWR for your vehicle should not be exceeded.

You can ask your dealer for our trailering information or advice, or you can write us at the address listed below.

National Owner Relations Department
16323 Shoemaker Avenue
Cerritos, California 90702

Weight of the Trailer Tongue

The tongue load (A) of any trailer is an important weight to measure because it affects the total or gross weight of your vehicle. The Gross Vehicle Weight (GVW) includes the curb weight of the vehicle, any cargo you may carry in it, and the people who will be riding in the vehicle. And if you will tow a trailer, you must add the tongue load to the GVW because your vehicle will be carrying that weight, too. See Loading the Vehicle for more information about your vehicle's maximum load capacity.


Object Number: 806596  Size: B2

If you're using a weight-carrying or a weight-distributing hitch, the trailer tongue weight (A) should be 10 percent to 15 percent of the total loaded trailer weight (B). Do not exceed the maximum allowable tongue weight for your vehicle.

After you've loaded your trailer, weigh the trailer and then the tongue, separately, to see if the weights are proper. If they aren't, you may be able to get them right simply by moving some items around in the trailer.

Total Weight on Your Vehicle's Tires

Be sure your vehicle's tires are inflated to the upper limit for cold tires. You'll find these numbers on the Certification label at the rear edge of the driver's door. Then, be sure you don't go over the GVW limit for your vehicle, including the weight of the trailer tongue.

Hitches

It's important to have the correct hitch equipment. Crosswinds, large trucks going by and rough roads are a few reasons why you'll need the right hitch. Here are some rules to follow:

    • If you'll be pulling a trailer that, when loaded, will weigh more than 4,000 lbs. (1 816 kg), be sure to use a properly mounted, weight-distributing hitch and sway control of the proper size. This equipment is very important for proper vehicle loading and good handling when you're driving.
    • Will you have to make any holes in the body of your vehicle when you install a trailer hitch?

If you do, then be sure to seal the holes later when you remove the hitch. If you don't seal them, deadly carbon monoxide (CO) from your exhaust can get into your vehicle. Dirt and water can, too.

Safety Chains

You should always attach chains between your vehicle and your trailer. Cross the safety chains under the tongue of the trailer to help prevent the tongue from contacting the road if it becomes separated from the hitch. Instructions about safety chains may be provided by the hitch manufacturer or by the trailer manufacturer. Follow the manufacturer's recommendation for attaching safety chains and do not attach them to the bumper. Always leave just enough slack so you can turn with your rig. Never allow safety chains to drag on the ground.

Trailer Brakes

If your trailer weighs more than 1,500 lbs. (680 kg) loaded, then it needs its own brakes -- and they must be adequate. Be sure to read and follow the instructions for the trailer brakes so you'll be able to install, adjust and maintain them properly.

Your trailer's brake system can tap into the vehicle's hydraulic brake system only if:

    • The trailer parts can withstand 3,000 psi (20 650 kPa) of pressure.
    • The trailer's brake system will use less than 0.02 cubic inch (0.3 cc) of fluid from your vehicle's master cylinder. Otherwise, both braking systems won't work well. You could even lose your brakes.

If everything checks out this far, then make the brake fluid tap at the port on the master cylinder that sends fluid to the rear brakes. But don't use copper tubing for this. If you do, it will bend and finally break off. Use steel brake tubing.

Driving with a Trailer

Caution: When towing a trailer, exhaust gases may collect at the rear of the vehicle and enter if the liftgate, trunk/hatch, or rear-most window is open.

Engine exhaust contains carbon monoxide (CO) which cannot be seen or smelled. It can cause unconsciousness and even death.

To maximize safety when towing a trailer:

   • Have the exhaust system inspected for leaks and make necessary repairs before starting a trip.
   • Never drive with the liftgate, trunk/hatch, or rear-most window open.
   • Fully open the air outlets on or under the instrument panel.
   • Adjust the Climate Control system to a setting that brings in only outside air and set the fan speed to the highest setting. See Climate Control System in the Index.
For more information about carbon monoxide, see Engine Exhaust

Towing a trailer requires a certain amount of experience. Before setting out for the open road, you'll want to get to know your rig. Acquaint yourself with the feel of handling and braking with the added weight of the trailer. And always keep in mind that the vehicle you are driving is now a good deal longer and not nearly as responsive as your vehicle is by itself.

Before you start, check the trailer hitch and platform (and attachments), safety chains, electrical connector, lamps, tires and mirror adjustment. If the trailer has electric brakes, start your vehicle and trailer moving and then apply the trailer brake controller by hand to be sure the brakes are working. This lets you check your electrical connection at the same time.

During your trip, check occasionally to be sure that the load is secure, and that the lamps and any trailer brakes are still working.

Following Distance

Stay at least twice as far behind the vehicle ahead as you would when driving your vehicle without a trailer. This can help you avoid situations that require heavy braking and sudden turns.

Passing

You'll need more passing distance up ahead when you're towing a trailer. And, because you're a good deal longer, you'll need to go much farther beyond the passed vehicle before you can return to your lane.

Backing Up

Hold the bottom of the steering wheel with one hand. Then, to move the trailer to the left, just move that hand to the left. To move the trailer to the right, move your hand to the right. Always back up slowly and, if possible, have someone guide you.

Making Turns

Notice: Making very sharp turns while trailering could cause the trailer to come in contact with the vehicle. The vehicle could be damaged. Avoid making very sharp turns while trailering.

When you're turning with a trailer, make wider turns than normal. Do this so your trailer won't strike soft shoulders, curbs, road signs, trees or other objects. Avoid jerky or sudden maneuvers. Signal well in advance.

Turn Signals When Towing a Trailer

The arrows on your instrument panel will flash whenever you signal a turn or lane change. Properly hooked up, the trailer lamps will also flash, telling other drivers you're about to turn, change lanes or stop.

When towing a trailer, the arrows on your instrument panel will flash for turns even if the bulbs on the trailer are burned out. Thus, you may think drivers behind you are seeing your signal when they are not. It's important to check occasionally to be sure the trailer bulbs are still working.

Driving On Grades

Reduce speed and shift to a lower gear before you start down a long or steep downgrade. If you don't shift down, you might have to use your brakes so much that they would get hot and no longer work well.

You can tow in DRIVE (D). You may want to shift the transmission to THIRD (3) or a lower gear, under heavy loads or hilly conditions.

When towing at high altitude on steep uphill grades, consider the following: Engine coolant will boil at a lower temperature than at normal altitudes. If you turn your engine off immediately after towing at high altitude on steep uphill grades, your vehicle may show signs similar to engine overheating. To avoid this, let the engine run while parked (preferably on level ground) with the automatic transmission in PARK (P) for a few minutes before turning the engine off. If you do get the overheat warning, see Engine Overheating.

Parking on Hills

Caution: Parking the vehicle on a hill with the trailer attached can be dangerous. If something goes wrong, the rig could start to move. People can be injured, and both the vehicle and the trailer can be damaged. When possible, always park the rig on a flat surface.

But if you ever have to park your rig on a hill, here's how to do it:

  1. Apply your regular brakes, but don't shift into PARK (P) yet. When parking uphill, turn your wheels away from the curb. When parking downhill, turn your wheels into the curb.
  2. Have someone place chocks under the trailer wheels.
  3. When the wheel chocks are in place, release the regular brakes until the chocks absorb the load.
  4. Reapply the regular brakes. Then apply your parking brake, and then shift into PARK (P).
  5. Release the regular brakes.

Caution: It can be dangerous to get out of the vehicle if the shift lever is not fully in P (Park) with the parking brake firmly set. The vehicle can roll.

If the engine has been left running, the vehicle can move suddenly. You or others could be injured. To be sure the vehicle will not move, even when on fairly level ground, use the steps that follow.

Always put the shift lever fully in P (Park) with the parking brake firmly set.

If the transfer case on a four-wheel-drive vehicle is in N (Neutral), the vehicle will be free to roll, even if the shift lever is in P (Park). Be sure the transfer case is in a drive gear -- not in N (Neutral).

When You Are Ready to Leave After Parking on a Hill

  1. Apply your regular brakes and hold the pedal down while you:
  2. • start your engine,
    • shift into a gear, and
    • release the parking brake.
  3. Let up on the brake pedal.
  4. Drive slowly until the trailer is clear of the chocks.
  5. Stop and have someone pick up and store the chocks.

Maintenance When Trailer Towing

Your vehicle will need service more often when you're pulling a trailer. See the Maintenance Schedule for more on this. Things that are especially important in trailer operation are automatic transmission fluid (don't overfill), engine oil, axle lubricant, belt(s), cooling system and brake system. Each of these is covered in this manual, and the Index will help you find them quickly. If you're trailering, it's a good idea to review these sections before you start your trip.

Check periodically to see that all hitch nuts and bolts are tight.

Trailer Wiring Harness


Object Number: 807796  Size: B3

Your vehicle may be equipped with a seven-wire trailer towing harness. This harness has a seven-pin universal heavy-duty trailer connector that is attached to a bracket on the hitch platform. The seven-wire harness contains the following trailer circuits:

    • Yellow: Left Stop/Turn Signal
    • Dark Green: Right Stop/Turn Signal
    • Brown: Running Lamps
    • White: Ground
    • Light Green: Back-up Lamps
    • Red: Battery Feed
    • Dark Blue: Electric Brakes

Your vehicle is also equipped with wiring for an electric trailer brake controller. These wires are located inside the vehicle on the driver's side under the instrument panel. These wires should be connected to an electric trailer brake controller by your dealer or a qualified service center.