69 Headlight door problem
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Pro
Joined: May 2001
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From: Yardley PA
69 Headlight door problem
Hi Everybody!
I haven't driven my baby for over a year (no insurance) and have to sell
I am just checking out everything and making sure that the buyer gets a functioning car. I noticed a problem that is news to me:
When I shut down the engine, it takes maybe 5 seconds and ONE headlight (driver side) opens with a hissing sound. Then it stays open until I fire up the engine, at which point in time it closes.
When the engine is running, everything opens and closes without problem or major delay. Any idea where I can start the troubleshooting? Since it's just one headlight and not both, I guess it must be a leak or worn actuator on that side, but how to be sure?
Thanks!
Stefan
I haven't driven my baby for over a year (no insurance) and have to sell
I am just checking out everything and making sure that the buyer gets a functioning car. I noticed a problem that is news to me:
When I shut down the engine, it takes maybe 5 seconds and ONE headlight (driver side) opens with a hissing sound. Then it stays open until I fire up the engine, at which point in time it closes.
When the engine is running, everything opens and closes without problem or major delay. Any idea where I can start the troubleshooting? Since it's just one headlight and not both, I guess it must be a leak or worn actuator on that side, but how to be sure?
Thanks!
Stefan
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Joined: Sep 2001
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From: Boxford Mass
there were a few posts on this topic, you may want to query the past posts for details.
A small leak in the control system would cause the system to open if there was enough vacuum in reserve.
I would follow the "hiss". I went thru a bunch of cheap actuator relays that leaked before i broke down ad bought a NOS piece.
A small leak in the control system would cause the system to open if there was enough vacuum in reserve.
I would follow the "hiss". I went thru a bunch of cheap actuator relays that leaked before i broke down ad bought a NOS piece.
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You most likely have a vacuum leak in the control side of the system. When you shut down the engine, you have a lot of vacuum in the vacuum tank. It's plenty to raise the lights.
What's happening is that there's a leak in the control or switch side. When you shut down the car, that system bleeds off fast. The relay in the front of the car sees the drop in vacuum and directs the vacuum from the tank into BOTH headlight actuators. It just happens that one of the headlights opens more readily than the other. They never go up exactly together, even in a perfect system.
The first thing I would check is the check valve. It's on the left side of the engine compartment near the firewall. One big hose going in from the engine, one big one going out to the vacuum tank and a small one going through the firewall. I'l probably just replace this and see what happens before trying to diagnose it any further.
The next step would be to check the small lines that go to the headlight switch, and the underdash override switch....and the switches themselves.
What's happening is that there's a leak in the control or switch side. When you shut down the car, that system bleeds off fast. The relay in the front of the car sees the drop in vacuum and directs the vacuum from the tank into BOTH headlight actuators. It just happens that one of the headlights opens more readily than the other. They never go up exactly together, even in a perfect system.
The first thing I would check is the check valve. It's on the left side of the engine compartment near the firewall. One big hose going in from the engine, one big one going out to the vacuum tank and a small one going through the firewall. I'l probably just replace this and see what happens before trying to diagnose it any further.
The next step would be to check the small lines that go to the headlight switch, and the underdash override switch....and the switches themselves.
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Pro
Joined: May 2001
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From: Yardley PA
Alright!
Things do make more sense now. I still haven't figured it out completely, but I'm on the right track. There is one thing that bothers me though:
The vacuum diagrams that I've seen show TWO switches or relays in the front- one for each headlight. I have only one and there are Ts coming off of that. it looks pretty original, the hoses going into the Ts are bigger than the ones going from the Ts to the headlights. (Looks like 9/32 going to the Ts and 7/32 going from the Ts to the headlights)
The relay is also dead-smack in the center. The hoses are the original style, most of them even still have the original color stripes.
Any idea if there are different versions of this?
For troubleshooting:
If I take a handheld vacuum pump and hook it up directly to the control inlet on the relay and pull a vacuum. Then I shut of the engine. The headlights should stay down, if the problem is on the controls side- right?
Cheers!
Stefan
Things do make more sense now. I still haven't figured it out completely, but I'm on the right track. There is one thing that bothers me though:
The vacuum diagrams that I've seen show TWO switches or relays in the front- one for each headlight. I have only one and there are Ts coming off of that. it looks pretty original, the hoses going into the Ts are bigger than the ones going from the Ts to the headlights. (Looks like 9/32 going to the Ts and 7/32 going from the Ts to the headlights)
The relay is also dead-smack in the center. The hoses are the original style, most of them even still have the original color stripes.
Any idea if there are different versions of this?
For troubleshooting:
If I take a handheld vacuum pump and hook it up directly to the control inlet on the relay and pull a vacuum. Then I shut of the engine. The headlights should stay down, if the problem is on the controls side- right?
Cheers!
Stefan
