The heater control switches. The fan works but, seems to when you but when you turn from heater to defrost to a/c nothing seems to change and the temperature control switch seems to not change. Looks like it is electronically controlled which activate the vacuum sensors under the dash, opens and closes vents. Is there a way to test this?
The model number is 16140094. Serial number is 2022769 Delco

#2 when you turn on the headlight switch the radio comes on.