2003 GMC Sierra 1500 "heater work truck" Questions

...not heat the truck now. Unfortunately the air conditioner won't go off so the heater can work. Help Try to disconect the battery cable(negative) for about 15 seconds to reset the ac/heater

work and engine temp.is normal.no water leaking from heater core.windows don`t fog up. the valve that allows the hot water into the heater core is not opening. most likely electronic issue. also check

...Heater and ac work thru front vents.....Is there a reset sequence to get defrost to work properly no,, the system works from a vacuum and has to be worked on in a service garage. sorry about the bad ...

...heater dont work on my 2004 gmc sierra 1500, engine(4.8) only the AC works in it... but the heater not anymore.... please help... and also the temperature gauge not working, it's only pointing ...

...for a while but has quit completely. Main fuse in fuse box is good, changed heater/ac digital control but still doesn't work, digital heater/ac control switch doesn't light-up? check the

Driver's side seat heater turns off after 30 to 45 seconds. When it goes off it also suts off passenger side. Passenger side works fine alone. Th heater relay is probably bad for the drivers side. ...

heater fan motor quit working already checked all fuses and relays check the fan switch in the dash and the fan motor connector for burning, if u find burned connectors replace them and the heater ...

2004 GMC Sierra Heater does not heat on low RPM The heater will blow only unheated air at idle or until I actually apply at least 1600rpm on the engine. It will heat just fine then. On the road it ...

...TRUCK- NO HEAT NEW THERMOS / GETTING HEAT IN RADIATOR LINE - FAN MOTOR IS WORKING - NO HEAT TO "IN" LINE TO CORE- NO SMELL- NO FOGGING NO WET FLOOR. hELP I am going to assume that you checked to make ...

2000 gmc sierra 5.3l heater does not get hot antifreeze is full thermostat looks ok replaced anyway. what else? After replacing the thermostat I pulled the heater hoses off and blew air through the ...