97 deville wont blow hot air

Did you replace your thermostat?

Probably the HVAC blend door actuator for the climate control, if you had heat after replacing all that, but yes as Met is asking is if the thermostat was replaced also?

Yeah i also replaced the thermostat

There is a Climate Control Vacuum valve, or a Air Conditioning Air Inlet Door Actuator that could be bad. One of them just letting in outside air.

IThe a c air cmes fine. i changed heater core, and blander door acuator hot air blow but does not come into vent the mechanic says HVAC amplifier or computer is need to resett the program second mechanic says turn on all lights etc and the disconnect the battery terminal one night nexd turn off the lights and try third mechanic says u need to reset the comuter by remove one 10 am fuse wait and reset and start it will work nobody knows what to do please help