Headlight Doors: Operation

Turning on headlight switch will automatically open headlight panel assemblies. The vacuum control manual valve is used to open headlights for service without turning on the lights. Manual valve is normally in a depressed (upward) position. With headlight switch off, vacuum is directed through switch to relay valve diaphragm and relay valve directs vacuum from reserve tank to back side of power actuator diaphragm holding headlight panels closed. When headlight switch is on, vacuum is cut off to relay valve diaphragm and spring in relay valve moves up. Vacuum is then directed to front side of actuator diaphragm moving headlight panels open. When the manual valve is pulled down, vacuum is cut off to relay valve and causes same action as when headlight switch is pulled on. The manual valve must be pushed in before headlights can be operated by the light switch.