Headlight Doors - Automatic: Testing

Use a vacuum gauge to test system for leaks. Vacuum should not drop when headlight switch is moved through the "OFF-PARK-ON" positions. If doors do not open, turn on lights and turn by-pass valve to vent position. If doors open, check hoses between switch and by-pass valve. If doors do not open with valve in vent position, check doors for binding and check vacuum lines between valve and doors. Replace kinked or damaged hoses, and any leaking components.