Vacuum Headlight Operation

[craig32]

Can anyone help me with a vacuum headlight dilemma? My headlights would not come up at all, either side. I replaced the driver's side actuator with a used one, now when I pull the light switch, the driver's side slowly begins to open. It makes it about half way open, then the other side slowly opens to about half way. If I pull a little on one unit, the other one drops accordingly - and if I apply light pressure down on it, the other one raises. Does this signify a lack of vacuum? How does one test the relays? Maybe the reserve canister? Anyone have any similar experiences? Thanks for your advice.

Craig

 

[Daryllawman]

Hello Craig......I was just getting ready to post the same thing. I am having trouble with my 79 headlights.....I think the lines are crossed. I just had the Engine rebuilt and I don't they hooked the lines up right.....

 

[jdp6000]

It does sound as though your lines are crossed.

Firsr check your actuator seals. You have two hoses going to each actuator. disconnect them one at a time from the valves mounted in the center of the front end. Blowing on one hose will make the light go up. sucking on the other hose will mak the light go down. You should fell total resistance when blowing...no air leaking out. You should feel total resistance when sucking...unable to suck more air in. If this is what happens the actuators are good. If the hose going to the front one leaks its an easy fix...magicians hat shaped seal that costs about $6. If there is leakage from the hose going to the rear of the actuator it can not be fixed.

Anyway once you have figured out the actators are good. Test the hoses going to the valves from the canister and the engine. There should be a total seal.

If all is good play around with the hoses that go to the actuators.Both the left and right will be in the same positions. Reversing the hoses will cause your problem. I looked at mine (1982). Rear actuator hose goes to the very top of the valve and front actuator hose goes to the very bottom. Middle is the vac supply.

Hope this helps.
Jim

 

[jdp6000]

Craig you definitely have your hoses reversed....

Jim

 

[74bigblock]

Craig you definitely have your hoses reversed....

Jim

That's what she said!

 

[Bob Chadwick]

Headlight assistance and the missing diagram. Download the diagram and use an image viewer to make it larger.

 

[craig32]

jdp,

I did all that before I posted here. The hoses are exactly as you stated, which is what the diagram I consulted showed also.

Bob,

The diagram is way bigger than I can print. It seems like there's a lot more in your diagram than under my hood.
Thanks anyway.

Craig

 

[Vettehead Mikey]

Contrary to some of the posts above, the fact that one light goes up when you push the other down does not indicate that any lines are crossed. This is normal operation, naysayers should go out to their own cars and try it.

The fact that your lights are sluggish/stalled part way is most likely due to a massive vacuum leak somewhere in the system. Could be anywhere, including inside the car at the heater controls.

Fixing it just takes long hours of labour examining each component in turn till the offending part(s) are found. Mine had 5 separate leaks that needed fixing before the system would respond acceptably.

 

[Daryllawman]

In my case the lights will not go up or down. They light up but thats all.....I am going to check all of the lines this weekend....I have the diagram of the lines.....I will let you know what I find out...