Throttle Angle Vacuum Switch (Non-Turbo)

Switch is connected to the carburetor spark port. Switch is mounted on left fender apron, along with the cold temperature vacuum switch. See Fig 3.

When 3 in. Hg vacuum or more is applied to the switch, the electrical contacts open. A signal is sent to the ECU, telling it to operate system in the "Closed Loop" mode. When no vacuum is applied (idle and deceleration), the switch contacts are closed, the ECU operates system in "Open Loop" mode.

Fig 1: Feedback Carburetor Metering System & Fuel Diaphragm Assembly

Courtesy of FORD MOTOR CO.

Fig 2: Vacuum Solenoid Regulator (VSR)

Courtesy of FORD MOTOR CO.

Fig 3: Cold Temperature Vacuum Switch & Throttle Angle Vacuum Switch Assembly

Courtesy of FORD MOTOR CO.