GMC 1993 Suburban Owner's Manual page 151

Heater Outpuf
Optional Emgs'ne Block Heater
If your engine is equipped with an optional engine block heater, you can use
it during initial start-up in cold weather (20"F, -8"C, or lower) to help heat the
passenger compartment faster. Because an engine block heater warms the
engine coolant, your vehicle's heating system can provide some heat as soon
as you start the engine.
The use of an engine block heater also reduces the time
it
takes for the
engine
to
reach normal operating temperature, and shortens the time
it
takes
the heater to reach full output. For more information, See "Engine Block
Heater" in the Index.
Ekctronic Heatlng'i4ir Conditionby System
Function Dispiay
. . . .
~~
.........
~
K2305
If your vehicle has air conditioning, your heatinglair conditioning system will
look like this.
When
you
first turn on your vehicle's air conditioning, open the windows
to
clear the vehicle of hot air.
3-5