has been diong this since cold weather
car at operational temp fan works on all speeds just blows cold air on 2003 Buick Century
Make sure the 2 heater hoses are hot to the touch the same as the upper hose at operating temp, 180 - 200deg. If those are good, possible temp/blend door actuator, is it dual air control.
not sure about dual air control,it does just have 2 levers one for driver and one for passenger. they don't have actual temperature settings. just little slides that go from blue(cold) to hot(red) It almost seems like the a/c is "stuck" on. by the way thanks for the info
That is a dual control system, and usually if the actuator was bad it would effect one side or another, not usually both at the same time. Check your coolant level, it has to be full, and your heater hoses.
thanks so much for your help. I will check it out in the am
Ok good night
1 more answer
change the thermostat, if that doesn't work you need to replace the heater control valve/ heater core. or flush your coolant system three or four good times to get contaminated or sludgy fluid