MY 1981 has started doing somethig strange.All of asudden when I start the car the headlights open up and I have to close them manually?any ideas. Thank's Ron

 

My guess is you have a big vacuum leak somewhere between your headlight vacuum check valve and the tops of your headlight vacuum relays. First check the obvious: Did the bypass switch under your steering column get pulled down inadvertently? Did the vacuum hose going to the "T" at the headlight vacuum relays become disconnected? Did the vacuum hose going from the smaller of the 2 ports out of the check valve to the firewall become disconnected from the check valve?

If the answers to those 3 questions are "No", then you'll be troubleshooting the headlight vacuum hoses, components, and connections under the dash looking for leaks. If you can you hear hissing coming from under the driver's side dash when the motor is running, that's the place to start. My sticky on "How Your Headlight Vacuum System Works" has some troubleshooting tips plus links to other tips that might help.

Please post your fix on here so all can learn from your experience.

Good Luck!
Jerry

 

Does this help ??? http://forums.corvetteforum.com/c3-t...tem-works.html