Large success today. All thanks to you!
I started with the flap control diagnosis. All flaps failed. Only outlet working was the defroster. So, either I had a leak in one of the control pods causing the system to lose air, or, I had no vacuum to Y11 to begin with.
So, I started by focusing on the Y7, the vacuum distribution block. I first made sure that I had vacuum from the engine (the grey line on port 7). I had 15" of vacuum. Great. Then tested the clear line running from my newly repaired PSE. Variable vacuum.
So then disconnected a random line from the block, and tested the vacuum coming out of the block. Nada. Zilch. So, I had a leak somewhere.
One by one, disconnected the lines and checked them to see if they held pressure. Lines 3 (headlight range input), 9 (headlight range output), 12 (at resevoir), and 13 (ac resevoir) all leaked. So, I blocked off the ports on the block for the leaking lines (except for one) and tested to see if the block held vacuum. Nada, zilch. So, my vacuum distribution block is bad.
Next up: Jumpering. Tee'd together the grey line from the engine, the clear line from the PSE, and the grey-green line that supplied vaccuum to the Y11 valve. So now the Y11 was being supplied a known supply of vacuum (sans reservoir).
Turned on the engine, put the system into Auto mode, and fell out of the car! For the first time since I've had the car all the vents work!!!!
So, I then ran through the flaps test you so helpfully provided. All vents tested fine. So none of my control pods leak (so far. now that they are going to be used, I'll have to wait and see). I de-ox'd the electrical connector to Y11 while I was in there.
I've found a block (140 830 0485) on eBay and have ordered that.
So, two issues here.
1. Have to pull the wheel well liner and see why the resevoir is leaking. My money is on a disconnected line.
2. Should I put a check valve in-between the engine vacuum and the PSE vacuum? Common sense says to do this.
Again, I could not have done this without all the fantastic information you have provided. I think you should be lauded and notated as THE expert of the ventilation systems for these cars!