FORD 1999 Explorer - Manual (Page 174)

Safety chains
Always connect the trailer’s safety chains to the vehicle. 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 brakes are safe if
installed properly and adjusted to the manufacturer’s specifications. The
trailer brakes must meet local and Federal regulations.
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 your
trailer lamps conform to local and Federal regulations. See your dealer or
trailer rental agency for proper instructions and equipment for hooking
up trailer lamps.
Never connect any trailer lighting to the vehicle’s taillamp
circuits, because it may damage the electrical system resulting in
fire. Contact your local Ford dealership for assistance in proper trailer
tow wiring installation. Additional electrical equipment may be
required.
Using a step bumper
The rear bumper is equipped with an integral hitch and requires only a
ball with a 19 mm (3/4 inch) shank diameter. The bumper has a 1 590 kg
(3 500 lb.) trailer weight and 159 kg (350 lb.) tongue weight capability.
Use a frame-mounted weight distributing hitch for trailers over 1 590 kg
(3 500 lb).
Driving
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