1993 GMC Suburban Owner's Manual - Page 151

Heater Outpuf Optional Emgs'ne Block Heater If yourengine is equippedwithanoptionalengineblockheater, you canuse it during initial start-up in cold weather (20"F, -8"C, orlower) to helpheatthe passengercompartmentfaster.Becauseanengineblockheaterwarmsthe enginecoolant,yourvehicle's heating systemcanprovidesomeheatassoon as you starttheengine. it takes for the The use of anengineblockheateralsoreducesthetime engine to reachnormaloperatingtemperature, and shortensthetime it takes theheater to reach full output.Formoreinformation,See"EngineBlock Heater" in the Index. Ekctronic Heatlng'i4ir Conditionby System Function Dispiay ...~~ ~ ... K2305 If your vehicle has air conditioning, your look like this. heatinglair conditioning system will to When you first turn on your vehicle's air conditioning, open the windows clear the vehicle of hot air. 3-5