Headlight Doors - Automatic: Operation
Pulling out headlight switch knob actuates the distribution valve on back of switch. Vacuum is then applied to vacuum motors, opening headlight covers. Distribution valve also provides a vacuum relief (exhaust) port to side of motor diaphragm without vacuum. When headlight switch is pushed in, vacuum supply and relief ports are reversed and headlight covers close. The reserve vacuum reservoir provides vacuum storage for limited headlight cover cycling. A reservoir check valve is used to prevent vacuum leakage back to engine and is located in vacuum supply line.
Headlight covers on all models have springs built into each motor. Vacuum applied to vacuum motors during closing overcomes spring tension. A by-pass valve is located in vacuum lines between headlight switch and vacuum motors. By-pass valve vents system to allow covers to open if they will not open automatically.