ad blue GMC SAFARI 1999 Owner's Manual

3-5 Rear Air Conditioning System (Option)
You may have rear air conditioning. The rear air
conditioning switch is located to the right of the heater
controls. Turn the switch toward HIGH for higher
airflow in the rear area. Turn the switch to the OFF
position to turn the system off.
Air Conditioning
Before using your vehicle's air conditioning, open the
windows to clear the vehicle of hot air. This reduces the
time it takes for your vehicle to cool down. Then keep
your windows closed for the air conditioner to work at
its best.
You can use MAX A/C with the temperature knob in the
blue area when it's really hot outside and you need to
cool the inside air quickly. MAX A/C lets in only a little
air from the outside.
If you first use MAX A/C, you can then use A/C with
the temperature knob in the blue are as soon as the
vehicle has cooled down, so outside air will be going
through your vehicle.
If your vehicle has rear air conditioning, setting it on
LOW may enhance the front A/C performance by
allowing trapped refrigerant in the rear lines to circulate.
The rear air conditioning system will only send cooled
air if the front system is on. It can still be used to
circulate air, even if the front system is off.
When the air conditioning, DEFROST or BLEND is on,
you may notice a slight increase or decrease in engine
speed, due to compressor operation. This is normal
because the system is designed to cycle the compressor
on and off to keep the desired temperature.

4-40 Trailer Wiring Harness
If you have the optional trailering package, your vehicle
will have an eight
-wire harness, including the center
high
-mounted stoplamp battery feed wire. The harness
is stored on the passenger's side of the vehicle near
the rear wheel well. This harness has a 30 amp battery
feed wire and no connector, and should be wired by
a qualified electrical technician. After choosing an
aftermarket trailer mating connector pair, have the
technician attach one connector to the eight
-wire trailer
harness and the other connector to the wiring harness
on the trailer. Be sure the wiring harness on the trailer is
taped or strapped to the trailer's frame rail and leave it
loose enough so the wiring doesn't bend or break, but
not so loose that it drags on the ground. The eight
-wire
harness must be routed out of your vehicle between the
rear door and the floor, with enough of the harness left
on both sides so that the trailer or the body won't pull it.
If you do not have the optional trailering package, your
vehicle will still have a trailering harness. The harness is
located near the passenger's side rear wheel well. It
consists of six wires that may be used by after
-market
trailer hitch installers. The technician can use the following color code chart
when connecting the wiring harness to your trailer.

Brown: Rear lamps.

Yellow: Left stoplamp and turn signal.

Dark Green: Right stoplamp and turn signal.

White (Heavy Gage): Ground.

Light Green: Back
-up lamps.

White (Light Gage): Center
High
-Mounted Stoplamp.

Blue: Auxiliary circuit (eight
-wire harness only).

Orange: Fused auxiliary (eight
-wire harness only).
Store the harness in its original place. Wrap the
harness together and tie it neatly so it won't
be damaged.