Mercury 2009 Grand Marquis Owner's Manual page 160

Tires, Wheels and Loading
WARNING: Towing trailers beyond the maximum recommended
gross trailer weight exceeds the limit of the vehicle and could
result in engine damage, transmission damage, structural damage, loss
of vehicle control, vehicle rollover and personal injury.
The GCW of your vehicle and trailer should not exceed 6,600 lb. (2,993 kg).
Preparing to tow
Use the proper equipment for towing a trailer and make sure it is
properly attached to your vehicle. See your authorized dealer or a
reliable trailer dealer if you require assistance.
Hitches
Do not use hitches that clamp onto the vehicle bumper. Use a load
carrying hitch. You must distribute the load in your trailer so that
10–15% of the total weight of the trailer is on the tongue.
Safety chains
Always connect the trailer's safety chains to the frame or hook retainers
of the vehicle hitch. To connect the trailer's safety chains, cross the
chains under the trailer tongue and allow slack for turning corners.
If you use a rental trailer, follow the instructions that the rental agency
gives to you.
Do not attach safety chains to the bumper.
Trailer brakes
Electric brakes and manual, automatic or surge-type trailer brakes are safe
if installed properly and adjusted to the manufacturer's specifications. The
trailer brakes must meet local and Federal regulations.
WARNING: Do not connect a trailer's hydraulic brake system
directly to your vehicle's brake system. Your vehicle may not
have enough braking power and your chances of having a collision
greatly increase.
The braking system of the tow vehicle is rated for operation at the
GVWR not GCWR.
Trailer lamps
Trailer lamps are required on most towed vehicles. Make sure all running
lights, brake lights, turn signals and hazard lights are working. See your
authorized dealer or trailer rental agency for proper instructions and
equipment for hooking up trailer lamps.
160
2009 Grand Marquis (grn)
Owners Guide, 1st Printing
USA (fus)