1980 t-bird hideaway headlights

Hideaway headlights close when engine is running but open when engine is shut off. Any suggestions?

Reply to
galaxiegirl70
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Do they open when lights turned on? Thats pretty important to help solve it.

If they open with lights on, engine running it's likely a leak.

Work your way back from the door (the headlight assy) actuator.

One or both of actuators, tubing to it, the control valve, may be leaking vacuum, or the control valve itself bad.

Reply to
Backyard Mechanic

The headlamp doors are vacuum operated and open when vacuum is removed. There is a leak somewhere in the system. You have a vacuum supply from the engine, a check valve, a vacuum chamber, a valve on the headlamp switch, and an actuator on each headlamp door. Visually inspect all of the rubber vacuum hoses for breaks or cracks, listen for leaks (hissing) near the actuators, switch, reservoir, and all connections. Make sure the check valve only passes air one way. At this age it could be any of the above, but back when this car was newer the headlamp switch and the check valve were common failure items. There may also be a manual valve under the hood, I don't remember if this vintage Tbird had one. If there is a leak, the engime will likely idle rough. If the check valve is defective, the engine will idle normally but the doors will open as soon as the engine is turned off.

Reply to
Tom Adkins

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