Headlights Open After Engine Shut Off

[DaveN54]

Re: 1972. Headlights opened very slowly when I bought the Corvette. Traced all the vacumm hoses (per troubleshooting guide) and located leaks at the headlight actuator relays. Replaced the actuator relays and the seals on the larger acuators. Now the headlight assemblies open as soon as I shut off the engine, about 75% of the time. ??? Any ideas?

 

[baxsom]

if i am understanding this troubleshooting manual myself it sounds like a check valve thing i believe.

 

[DaveN54]

The headlights worked great for a few weeks after the new actuators relays were installed, so I thought all was fixed until a couple weeks ago. I'll try replacing the check valve. Thanks for the suggestion.

 

[DaveN54]

It was the intake manifold check value.
Thanks for the suggestion.

 

[baxsom]

not a problem,
i had the same issue,
that troubleshooting manual is by far the best tool i have bought in a long time it seems.

 

[White75]

I always turn off the lights with the engine running to keep the vacuum pressure up. As soon as I turn the engine off, it's almost impossible to close the lights on our vette. but as soon as I turn the engine on, they close.

 

[Vette79]

I always turn off the lights with the engine running to keep the vacuum pressure up. As soon as I turn the engine off, it's almost impossible to close the lights on our vette. but as soon as I turn the engine on, they close.

I believe this is normal. Please correct me if I'm wrong.

 

[White75]

I believe this is normal. Please correct me if I'm wrong.

It's normal. you just have keep some vacuum pressure up (whether it's in the canisters or not) to open and close them. Some cars may hold the pressure a bit longer after engine shutoff and can close the lights successfully after the engine is off.

 

[Vettehead Mikey]

I believe this is normal. Please correct me if I'm wrong.

A properly functioning (leak free) system will hold vacuum for severals hours, if not a day or two.