I have a 1997 GMC Sierra c1500 with a 4.3L V-6. all of a sudden my vents are blowing hot air no matter the position of the temperature control switch. i assumed that it would be my heater control valve that is typically in line with the heater hoses and the heater core. I traced them very thoroughly, and there is no valve! I heard that 95, 96 and 1/2 of 97 have an electronic control valve, but wouldnt it still have to be in line with the heater core? or does it just block the air from flowing past the heater core and the heater core alway has water passing through it? lots of questions please help!
Yep, air mix door isn't working. Need to figure out how it operates. Some are cables, some are electric. Some may even use manifold vacuum.
Temperature is controlled by an air mix door inside the HVAC compartment. This door is either electrically actuated if you have an electronic climate control system, or a cable for manual control. Most probable cause is a failed electric actuator (air mix door control module).
SOURCE: 93 gmc sierra heater not working
THERMOSTAT REPLACE IF NOT SEE IF HOSES ARE CLOGGED SHOT OF AIR COULD HELP OR DISSCONNECT BATTERY CABLE 10-15 MIN CONNECT BACK TRY HEATER
SOURCE: 1986 VW Golf heater blows cold air
The heater in your car depends upon a flow of hot coolant going through the heater core in order to get hot air into the car. If the heater core is partially plugged, it will restrict the flow. If you have a head gasket that is putting exhaust into the cooling system, it will eventually get into the heater core. When this happens there is no coolant in the heater core to make the air warm. If the water pump vanes have corroded away the result will be very poor coolant circulation causing the heater to not blow hot air. If your car is equipped with a heater control valve that is not functioning properly, the coolant flow will be restricted. One or a combination of these factors is likely the culprit in your case.
if the car is not overheating, the thermostat is working fine.... replace or flush the heater core multiple times to try and eliminate sediment build-up.
SOURCE: Heater Core coolant flow 97 F250 Powerstroke
The one that comes out directly from the engine block
SOURCE: heater blow cold air in my 1994 Honda Accord (4
Yes clogged heater core may be the answer in your case .
395 views
Usually answered in minutes!
×