1999 GMC Sierra 1500 Pickup Owner's Manual - Page 164

Comfort Conhvls & Audio Systems Heating System (Without Air Conditioning) K2441 If your vehicledoesnothaveairconditioning,thisiswhatyourheating systemwill look like. Fan Knob Theknobontherighthasfourpositions. toward (t). To decreasetheairflow,turn To increasetheairflow,turnit it toward (-). Temperature Lever Thebottomlever lets youselectthetemperature of theairflowingintoyour (t) forwarmerair.Movetheleverleft vehicle.Movetheleverrighttoward toward (-) forcoolerair. Function Lever Thetoplevercanbemovedtothreedifferentheatingfunctions. Defrost(Right): Thissettingoperatesthedefroster.Heatedaircomesout or iceonthewindshield. nearthewindshield.Usethiswhenyougetfog Heater(Center): Heatedaircomesoutnearthefloor.Thisisbestfor weather. Vent (Left): The air comesoutattheventsonyourinstrumentpaneland at your front side windows. Placing the lever between positions sends air out both vents. cold 3-4