Shayster1969

When I turn the lights on the doors come up and stay up but when I turn them off the doors come up and go down as the vacuum changes. I have switched my wiper relay for the headlight relay to eliminate that as the source of the problem but the same thing occurs. Are both relays bad? Has anyone experienced that before or have a tip on where to look next?

DUB

I would bet that your vacuum storage tank (under your left top hood surround area) has leak in it or it can not hold good vacuum....because....the reason your headlight doors are coming up and going down WHEN you have the headlight switch OFF...is because the vacuum is changing on the SMALL HOSE that controls the actuator relay function

When NO vacuum is on that small hoe..the actuator relay routes the vacuum to OPEN the door.....When there IS vacuum on the small hose...then it routes the vacuum to CLOSE the door.

SO...if your vacuum is changing ( up and down) ..then the relay is doing the same thing. Hopefully your vacuum check valve is good...thus allowing your vacuum storage tank to be able to store vacuum. Your vacuum system MUST be able to store vacuum....or this problem will not go away.

DUB

69Vett

you have a leak on headlight system.

Reaper19

Had similar issues last year, after replacing and rebuilding most of the parts in the system I found the new vacuum check valve was bad and filter defective. I put the originals back in and the lights worked up and down like new. All my parts in the system did need to be replaced and rebuilt, but if you bought a new check valve and filter, check both again. Test the check valve to make sure it is not leaking vacuum back into the engine. I worked with the vendor and explained the testing I did, they agreed the parts were defective, great service and tech, they sent out new replacements. Lesson learned, new parts can also be defective, test them also before installing.

Good Luck

Jebbysan

Have checked the override under the steering column to make sure it is pushed all the way up? Also, check and make sure the line going to it are ok and that there is not a crack on the two ports...it is a cheap plastic switch......anyway as DUB said.....it is most likely the hose the activates the relay...the small hose on top of each one.....this is the same hose that has problems with big cams and low vacuum.


Jebby

fazang

Just came across this.
http://www.corvette-101.com/vacuum.htm

best explanation i have seen in years.
-ALF