GMC 1997 Safari Owner's Manual page 211

Trailer Brakes
If your trailer weighs more than 1,000 lbs. (450 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 brake system can tap into ybur vehicle's
hydraulic brake system, except:
e
0
e
Don't tap into your vehicle's brake system if the
trailer's brake system will use more than 0.02 cubic
inch (0.3 cc) of fluid from your vehicle's master
cylinder. If it does, both braking systems won't work
well. You could even lose your brakes.
Will the trailer parts take 3,000 psi (20 650 kPa) of
pressure? If not, the trailer brake system must not be
used with your vehicle.
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
A
C ' uTION:
If
you have a rear-most window open and you
pull a trailer with your vehicle, carbon monoxide
(CO) could come into your vehicle. You can't see
or smell CO. It can cause unconsciousness or
death. (See "Engine Exhaust" in the Index.) To
maximize your safety when towing a trailer:
Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
Keep the rear-most windows closed.
0
If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with the
fan on any speed. This will bring fresh,
outside air into your vehicle. Do not use
MAX A/C because it only recirculates the
air inside your vehicle. (See
''
Comfort
Controls" in the Index.)
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