AC/Heater stuck Mode door

[Chickenman]

Well, I've made some progress. I'm getting some air to Defroster vents now, Not 100% but about 50%.

 

Here's what I found. 

 

1: Disconnected linkage from Mode Vacuum Pot and both linkage and door moves freely. But connected to Mode pot the linkage only moves part way.

 

2: Took off Mode pot to have a look at it. Mode pot is free and holds vacuum. Here's the hidden deal. The Mode pot has a slotted attachment bracket. It is adjustable up and down. Mine was too far down and was not pulling linkage far enough open. After adjusting the Mode pot to it's highest installed position, I am finally able to get " some " defroster action.

 

3: Even on full Defrost I'm still getting outside air coming through the center vents. It's almost like the system is in BI-Level... and I think it is. For the vacuum selector valve, the FSM shows a different Port configuration than what is actually stamped on the valve. ( Sarah previously commented on this I recall ). I connected the hoses as per the actual stamping's on the selector valve... and it's never worked right since. I'm going to re-route the hoses tomorrow as per the " Incorrect " FSM drawings and see what happens.

 

4: I checked the " Source " vacuum at the vacuum selector switch by connecting my vacuum gauge to the " Source " vacuum hose. Then I went for a drive and monitored vacuum gauge in Real Time. Car has a big camshaft and I thought that may affect operation. Apparently not. Lowest Vacuum shown from " Source " hose was 15". And that shoots up to 20" and higher as soon as you shift gears or Coast. Accumulator tank maintains that levels, with only a slow drain down if you sit idling for a while. 15" to 20" should be more than enough to operate the Vacuum pots properly.  

 

This test confirms that all of the hosing, Vacuum/Magnetic valves and Accumulator tank are holding vacuum correctly.

 

5: I've checked all the other Heater/AC pots and lines with my Mighty Vac. They all function and hold vacuum fine. That eliminates any vacuum leaks in those circuits.

 

6: Selector valve was cleaned and lubricated as per Sarah's DIY. No real issues were found, and I made sure to " clock " it right on assembly as per sarah's instructions. . Hmmm.... now that's something to double check. There are two ways it can go together, and maybe the " Clocking " isn't the same both ways. 

 

More fun tomorrow. Right now my shoulder is killing me, so time to take some Advil and watch the Mind Numbing box. Seinfeld should work.... 

 

 

[Chickenman]

Finally got it fixed!!!. Turned out to be two strange problems.

 

1: Mode door actuator pot was somehow jamming internally. Seemed to be an alignment issue. Played around with the mounting alignment and suddenly it worked.... 

 

2: Teeth on selector valve weren't engaging properly, so selector valve wouldn't rotate. Nothing appeared worn on either the sector gear or the valve gear, but the teeth were just barely catching on the bottom edge. I flipped the valve 180 degrees and the teeth engaged better.....

 

 

Anyhoo.. I finally have everything working 100%. It's nice to have heat on your feet without the center vents constantly blowing cold air in your face. And a Defroster that actually works.

 

Edit: Ended up attaching the hoses as per stamping's on selector valve.

Edited September 6, 2015 by Chickenman

[Captain Obvious]

Excellent. Glad it was that simple. Nice that you didn't have to discharge the whole A/C system and pull the dash to fix it.

 

Enjoy the warm toes.