No HEAT on 1992 Cadillac DeVille

Air works great but now that cold weather is here I have no heat. Could it be the thermostat or the temp sensor switch?

2 answers 1 comment
Start by checking engine temperature - see if it gets actually hot. Check the inlet and outlet hoses of the heater core - scalding hot, or just warm? If they are both scalding hot, then you are looking at a temperature control issue inside the car.
Thanks Dave I'll look at this.
actuater is bad