1972
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,026
Likes: 4,174
From: US-PNW
Do the vacuum-operated headlights open as they should?
Does the wiper door open and close with the over-ride valve under the steering column?
WOW, I was way off base with the assumption we were talking about the wiper door! I'll slink back under my chair.
Last edited by barkingrats; Oct 2, 2022 at 11:33 AM.
Advanced
Joined: Sep 2021
Posts: 88
Likes: 40
If by ‘recirculation canister’ you mean the actuator that opens the recirculation vent by passenger foot, make sure that door opens easily by hand.
I have a 72 with A/C I got in June and have also been troubleshooting air system. My actuator was working fine as well but my recirc door was seized shut.
I have a 72 with A/C I got in June and have also been troubleshooting air system. My actuator was working fine as well but my recirc door was seized shut.
Melting Slicks
Joined: Feb 2018
Posts: 2,321
Likes: 720
From: Marietta GA
There are two vacuum operated doors when you have factory AC. There is a door on the passenger side outside (near the A pillar) that closes when the car is started. Sounds dumb, but that is the way it works. I believe that when you use the normal AC setting the door will open to let in the outside air. When you call for Max AC, the door will close. There is a second vacuum operated door on the passenger side kick panel that operates in conjunction with the door outside the car, to let in outside air. I rebuilt both doors with new rubber seals, and tested the vacuum motors with a hand held vacuum pump. If both units test ok with a vacuum pump, start looking at the vacuum lines or the vacuum selector switch.
Instructor
Joined: Aug 2010
Posts: 187
Likes: 10
From: Western OK
I had the same issue. I replaced the vacuum canister for the flapper that mounts outside the cabin in the area between the fender and cowl. It requires removing the wiper door and the mechanism for it. It is a chore, but doable. It takes some jiggling around to get the vacuum canister and flapper assembly out and the new one in. The worst part is putting the wiper door back on. Oh put rags below the flapper to keep the screws from going down where you can’t get them.
I was able to check mine buy applying vacuum to the hose that goes to the flapper with a hand pump. I had vacuum going to it but no movement. Made a difference when done.
I was able to check mine buy applying vacuum to the hose that goes to the flapper with a hand pump. I had vacuum going to it but no movement. Made a difference when done.
Thread Starter
Instructor
Joined: Sep 2021
Posts: 103
Likes: 29
From: Fort Worth, Tx.
When using hand pump on actuator door opens. Vacuum selector switch is new. When moving switch to normal a/c temperature blend door closes, and it blows out dash vents. But when moved to heat actuator won't vent allowing it blow out floor vent.
I have other issues that are more troubling. Compressor runs in every position. Vent, heat, off. Key on, compressor clutch engages. Blower also runs in off position. I upgraded the poa valve using temperature cut out switch instead of the pressure cut out switch. I can't find the blocker relays. I have a small gauge orange wire without a connector taped to the black blower ground wire. There is also vacant two terminal plug in harness on top of evaporator case, under the hood. It has two light blue wires on one terminal and I can't remember the color of the other wire.
I don't know if the vacuum part of the system worked caused I never checked. I do know the compressor didn't run all the time. So that part is something I did when I replaced the evaporator and removed dash to adjust blend door cable.
I have other issues that are more troubling. Compressor runs in every position. Vent, heat, off. Key on, compressor clutch engages. Blower also runs in off position. I upgraded the poa valve using temperature cut out switch instead of the pressure cut out switch. I can't find the blocker relays. I have a small gauge orange wire without a connector taped to the black blower ground wire. There is also vacant two terminal plug in harness on top of evaporator case, under the hood. It has two light blue wires on one terminal and I can't remember the color of the other wire.
I don't know if the vacuum part of the system worked caused I never checked. I do know the compressor didn't run all the time. So that part is something I did when I replaced the evaporator and removed dash to adjust blend door cable.
Melting Slicks
Joined: Feb 2018
Posts: 2,321
Likes: 720
From: Marietta GA
First please read the how to in the Willcox Tech Web Site on Vacuum for HVAC. They, along with others explain how even the new vacuum selector rotary switches are bad and leak. The compressor turn on is controlled by an “exposed” leaf switch located on the bottom of the HVAC Control. When the roller is turned to AC the switch on the bottom is engaged. Have you cleaned/refurbished your HVAC Control? Not a bad job, new plastic lens, wheels, and assorted parts.
