For 1990-2009 cars

The heater and A/C vacuum solenoid operates the vacuum actuators to control the following functions:

• | The air intake

• | The discharge locations

Inside the A/C solenoid switch assembly are 4 solenoid-actuated vacuum valves that respond to the heater and A/C control electrical signals. The vacuum valves vent or supply the vacuum to the vacuum actuators. By energizing various valve combinations, the heater and A/C control determines whether the air is directed to the following locations:

• | The floor outlets

• | The panel outlets

• | The defroster outlets

The heater and A/C control also determines the following conditions:

• | Whether outside air draws into the system

• | Whether inside air recirculates