Fresh air vent passenger side
Thread Starter
Melting Slicks
Joined: Feb 2018
Posts: 2,315
Likes: 717
From: Marietta GA
Fresh air vent passenger side
On my 73 Vert with AC, I repaired the exterior fresh air vent (located below the passenger side wiper blade) last year. The vacuum motor operates correctly, but I am concerned that I installed the door Backwards. The vent door closes once I start the engine, so after I turn off the engine, the door pops open. When the car is sitting, the open vent door could let in water/trash? I looked in my AIM and Service Manual without any luck. On the Forum I have seen conflicting information. It just seems that the door should remain closed when the Heater or AC is not turned on. At the car shows I attend, it seems the fresh air vent doors have been removed. A picture of a correctly installed fresh air vent door would be appreciated.
Team Owner
Joined: Jun 2000
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From: Southbound
Cruise-In II Veteran
Thread Starter
Melting Slicks
Joined: Feb 2018
Posts: 2,315
Likes: 717
From: Marietta GA
Thanks for everyone getting back with the correct operation of the fresh air vent. Now all I have to do is uninstall and reverse the way it sits in the vent space. This is what happens when people are lazy and don’t take any pictures before they remove an assembly. I will blame it on the excessive heat in my garage, around 95.
I know an air conditioner is in my future.
I know an air conditioner is in my future.
Instructor
Joined: Dec 2011
Posts: 189
Likes: 54
From: Virginia
I have a 1973 A/C also and the plenum vent is open when the car is off. I agree that it would make more sense to have the vent door being closed when the engine is off. I tried to take a picture but the screen is blocking the shot.
Here's the page from the AIM. It shows the vent door located inside the plenum opening with the vacuum actuator attached behind the vent door. View A is showing the components as if you are looking at it from the driver's fender.
Plenum Valve for 1973 with A/C
Thread Starter
Melting Slicks
Joined: Feb 2018
Posts: 2,315
Likes: 717
From: Marietta GA
Thanks for the information. I found the page in the AIM (with your help) and it confirms that I assembled the new door and vacuum motor correctly. Yesterday, I pulled the unit out and decided that it was installed correctly after all. It does seem odd that the door pops open after the engine is shut off. Do you think we both have a vacuum leaks on the HVAC System, and that is causing the door to open? I replaced the rubber hoses on my headlight system, but have not the hoses on the HVAC System. Should the HVAC System hold the vacuum?
Eli
Eli
Instructor
Joined: Dec 2011
Posts: 189
Likes: 54
From: Virginia
After shutting the engine, I've always lost the vacuum after a few minutes. I always assumed that was just the way it was supposed to work with the plenum door.
Last edited by vettz73; Oct 4, 2019 at 09:01 AM.
Thread Starter
Melting Slicks
Joined: Feb 2018
Posts: 2,315
Likes: 717
From: Marietta GA
I replaced all the rubber hoses on the headlight system, and after a few minutes all the vacuum is lost. My friend checked his 78 and he looses vacuum to the headlights after a few minutes like me. I have not checked each vacuum motor to see where the leak is coming from. I have a small vacuum/pressure gauge from HF and I will try to find out where the vacuum is leaking. If the HVAC System vacuum didn't leak, then the door would stay closed after the engine was turned off. The big car show in Atlanta is this weekend, so I will see what other C3 owners have to say. Thanks for your help.
Eli
Eli
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Thread Starter
Melting Slicks
Joined: Feb 2018
Posts: 2,315
Likes: 717
From: Marietta GA
Vetz73
This afternoon I started the engine and after the fresh air door closed, I clamped the hose, then turned off the engine. I waited 30 minutes and the door remained closed. Next I clamped the main vacuum line at the fire wall going to the HVAC Control. The door immediately opened. This tells me I have a leak at the vacuum switch (5 or 6 position). It’s a pretty big job as you have to remove top of the console, so I will wait until the weather gets cooler. From now on when I wash my car, I will put a clamp on the hose, to keep the door closed.
Eli
This afternoon I started the engine and after the fresh air door closed, I clamped the hose, then turned off the engine. I waited 30 minutes and the door remained closed. Next I clamped the main vacuum line at the fire wall going to the HVAC Control. The door immediately opened. This tells me I have a leak at the vacuum switch (5 or 6 position). It’s a pretty big job as you have to remove top of the console, so I will wait until the weather gets cooler. From now on when I wash my car, I will put a clamp on the hose, to keep the door closed.
Eli
Instructor
Joined: Dec 2011
Posts: 189
Likes: 54
From: Virginia
Eli
Thanks for the update.
I never replaced the HVAC hoses inside the car because the hoses on the HVAC control are molded directly to the control and there are no vendor supplied replacements for the molded control. They say you can cut the hoses close to the control and use vacuum connector tubes to mate the new hoses to the control.
I'm interested to see your results when you tackle that job.
Thanks for the update.
I never replaced the HVAC hoses inside the car because the hoses on the HVAC control are molded directly to the control and there are no vendor supplied replacements for the molded control. They say you can cut the hoses close to the control and use vacuum connector tubes to mate the new hoses to the control.
I'm interested to see your results when you tackle that job.
Thread Starter
Melting Slicks
Joined: Feb 2018
Posts: 2,315
Likes: 717
From: Marietta GA
Vetz73
You are correct, you can only buy the metal position rotary vacuum switch. I have watched the video from Willcox and it looks pretty simple, when you are doing the repair at your bench. My plan is to try and find a used rubber connector that goes on the metal rotary switch and install my new hoses at my workbench. Then once I have all the new hoses attached, I will connect them to each vacuum motor. I don't know how hard it will be to find the rubber connector? I will keep you updated. At least now I can keep the door closed when I wash the car.
Eli
You are correct, you can only buy the metal position rotary vacuum switch. I have watched the video from Willcox and it looks pretty simple, when you are doing the repair at your bench. My plan is to try and find a used rubber connector that goes on the metal rotary switch and install my new hoses at my workbench. Then once I have all the new hoses attached, I will connect them to each vacuum motor. I don't know how hard it will be to find the rubber connector? I will keep you updated. At least now I can keep the door closed when I wash the car.
Eli