On my '73, when my headlights are on and I shut the engine off before pushing the headlight switch, the headlights stay on and remain in the up position. If I then push the headlight switch in, the lights will turn off but not close. I have to restart the car to get them to go down. Is this normal? If not, is there something in particular that would be causing this?

Thanks everyone.

DC

 

There is a vacuum leak so the vacuum resovoir is depleted shortly after you shut off the engine.

 

Do the pinch test on the hose between the intake manifold and the check valve to see if its the check valve causing the problem.

 

Yes, that's a good place to start. If you are lucky, that will be the problem.

 

Wasn't lucky. The check valve tests okay. I do have a bad rod seal on the drivers head light actuator. Could the bad rod seal allow the vacuum reservoir to bleed off? The passenger side headlight pops up right away. The drivers side headlight takes a while but eventually comes up most of the time. Every now and then I'll have to help it up.

I had diagnosed the bad rod seal a couple of months ago and was getting ready to order the parts when I remembered to ask about the headlights not closing when the engine is shut down. When I did the original diagnostic the vacuum reservoir tested good but I only left the handheld vacuum pump/gauge on for a short time.

Also, I didn't state the issue correctly in the first post. When I kill the engine, the headlights remain on and up until I push the headlight switch. Then the lights go off but they remain up until I restart the engine.

I have replaced both the headlight switch and the override switch recently. I haven't ran the Vette much at night yet and so I could be wrong but if I remember correctly, the headlights did not close on engine shutdown even before I changed both switches. The override switch is working as it should.

Any other possibilities to check?

DC

 

Yes if the headlight switch is left on and the lights up a bad shaft seal will bleed the vac reservoir very fast.You should have had a rough idle when the headlights were up.

 

I'll go ahead and order the parts I need to fix the rod seal. Might as well go ahead and do both sides.

I didn't really notice a difference in idle quality with the lights on. My idle is a bit rough anyway so I may be used to it and didn't notice it getting worse. I'll try to better observe the idle with the lights on next time I drive it. Thanks for the help.

DC

 

DC3,

Once you have your actuator fixed, run a test on the system to make sure you don’t have any leaks.

It’s real simple to do:

Pull the main vacuum hose off the intake and with the car at operating temperature take a vacuum reading. Now attach the hose back on the intake and pull the hose from anywhere in the system. The vacuum at any point on the system should not exceed 1 hg. of vacuum. If you exceed this vacuum variance anywhere, block of different areas of the system to find your leak.

It’s time consuming to do this, but you can narrow down the exact part that is leaking and it’s cheaper than guessing and buying parts you don’t need.

Willcox Inc.

 

Hi Wilcox,
Your method of finding a leaking actuator or relay is GOOD idea.
I've found that sometimes just cutting a 1/2" off the end of the hose, at the connection so you have a 'new' seal, cures some leaks. There's usually more than enough length to allow that.
Regards,
Alan

 

Will do. Thanks for the help. I placed the order tonight from your website for the repair kit.

DC

 

I'll give this idea a go as well. Previous owner replaced everything but now everything is 10 years old even though it has seen little use. I ran some errands tonight and for whatever reason the passenger side light starting going down if I kill the engine and then push the switch but the drivers side still stays up. Once the rod seal kit arrives, I should be able to get it installed and then diagnose any remaining problems.

DC

 

Your headlight switch will allow power to the headlights with the engine turned off and even with the key out of the ignition. At least that is how it works on my 70. The fact that the headlights stay up is a vaccum problem as has been stated previously.

 

That is how mine is working as well. I figured the electrical side of the operation was okay. I find it interesting that all of a sudden one headlight will now lower like it should but the other stays up when I shut down.

DC

 

Ok, so while we're on the subject.......... Does anyone make and or distribute a "kit" for the vacuum systems? In other words, a kit that contains all the necessary hoses, complete with colored strips and other components for the various vacuum systems on these Corvettes? If not, Where can these color striped hoses be found?

 

If I read this right you shut the engine OFF with the lights on and buckets up - then you push the light switch in and the buckets stay up? That's normal operation as far as I know - the vacuum resevoir will bleed down on it's on after the engine is shut off on it's own accord. It just depends on how long you wait between engine off and pushing in the light switch.

 

All the Vette parts suppliers sell them. Here is the ZIP one.

http://www.zip-products.com/Zip/prod...B7F478F66DBDF0

 

Yes, you read it right. But I don't wait at all after shutting off the engine to push the switch in - just long enough to recognize I forgot the turn the lights off and then hit the switch. As I mentioned above, when I first got the Vette, both lights would stay up in this situation but Monday night, the passenger light began closing when I pushed the switch but the drivers side still stays up.

Hopefully, the actuator rod seal kit I ordered (and needed anyway) will do the trick. It didn't really bother me that both lights stayed up, I was just going to train myself to shut them off before killing the engine but now that one stays up and one doesn't, I'll be more interested in getting the system to work properly.

Thanks for the help.

DC

 

I would recommend the Dr. Rebuild kit. I have heard that his diagram is dead on and there can be some problems with some of the others. I do not know first hand as that project is still down the road and my vaccum system works fine right now.

 

Vacuum, as well as electrical, is plumbed through the headlight switch. That leads me to believe that switching off the headlamps after ignition is off might just keep the lights in the 'up' position. I can't say that I know for sure how they are supposed to work, but that could be 'normal' operation. (I'm working on the engine compartment of my car right at the moment, so I can't check it out.)

 

As I recall when my car was new, you could get about one or two openings or closing of the headlights after the engine was turned off. These days, although my headllights work fine and open and close in about 2 seconds, there is no way they will close after the engine is shut off. I suspect I have a small vacuum leak somewhere, and plan to check the check valve one of these days . The wsw door opens and closes very fast, like SNAP and it's open, SNAP and it's closed.

I don't drive it at night or in the rain, so it really isn't a big issue at this time.