1993 Chevrolet Suburban Owner's Manual - Page 150
1993 Chevrolet Suburban Manual
Page 150 highlights
Heater Output Optional Engine Block Heater If yourengine is equippedwithanoptionalengineblockheater,youcanuse -8OC, or lower) to helpheatthe itduring initial start-upincoldweather(20"F, passengercompartmentfaster.Becauseanengineblockheaterwarmsthe enginecoolant,yourvehicle'sheatingsystemcanprovidesomeheat as soon asyoustarttheengine. Theuseofanengineblockheateralsoreducesthetime it takesforthe enginetoreachnormaloperatingtemperature,andshortens the time it takes the heater to reach full output.Formoreinformation,See"EngineBlock Heater"intheIndex. Electronic Heating/Air Conditioning System Function Display I ...I K2: If your vehicle has air conditioning, your heating/air conditioning system will look like this. When you first turn on your vehicle's air conditioning, open clear the vehicle of hotair. the windows to 3-5