300SD Shutoff issue - Vacuum leak

[DeltaFox]

I recently bought an 83' 300 SD. I am currently trying to get the engine to shut off like its intended too. Over the past week or so it has gotten worse and worse. I use to shut off about 20 seconds after the key was turned off and now can go for about 3 minutes and die painfully.

Here's what I have done so far.
1. Tested vacuum on the shut off valve. Works great after about 5 inches of vacuum.
2. Watched the vacuum pressure coming from the hard line hose to the shut off valve. Instantly pops up to 16 inches of vacuum after the key is turned to the off position.
3. Used a 'T', 3 way, connector and watched the system to see what happens. Vacuum slowly builds up from 0 to 5 inches of vacuum slowly. Been getting worse.
4. Replaced the rubber hose to the shut off valve and I have ordered extra 3 way and 4 way vacuum junctions to replace them all but do not have them yet.

What could be the cause of this? The system appears to work well when tested separately but when put together the vacuum slowly builds.

The other side effect of this as far as I can tell is that the vents in the car slowly change from the defroster to the main vents. When I disconnect the shut off valve they work perfect. Door locks work great too. Every system I have tested (doorlocks, transmission, EGR) works well.

Is there a good place to find out how to test the vacuum system, i.e. - disconnect this house with engine on and watch vacuum and see what it does?

My last question is how the heck do i remove the switch panel to get behind the radio and to the ACC system? Mine has no round turn knobs, only switches. I will try and include the picture of it at the bottom of this post.