Chevrolet 1994 Astro Passenger Owner's Manual page 76

Engine Coolant Heater (Engine Block Heater)
(Option)
-
1. Engine Coolant
Heater Strap
2. Engine Coolant
Heater Cap
In very cold weather, 0°F (-1 8 "C) or colder, the engine coolant heater can
help. You'll get easier starting and better fuel economy during engine
warm-up. Usually, the coolant heater should be plugged in a minimum of
four hours prior to starting your vehicle.
To use the coolant heater:
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord.
3. Plug it into a normal, grounded 1 10-volt outlet.
A
CAUTION:
NOTICE:
After you've used the coolant heater, be sure to store the cord as
it was before to keep it away from moving engine parts. If you
don't, it could be damaged.
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