1984 300SD Climate control gremlins

[peragro]

Well folks, still troubleshooting the ACC problems that began with a non-functioning heater.

-Heater brushes replaced, it works when hooked directly to 12V.

-Monovalve repair kit installed as I've been having odd heat issues for the last year.

-1 amp fuse placed in line between aux. coolant pump and ACC (brown/green wire)

-Pulled out PBU (push button unit/AKA ACC) and took it apart. Temperature gauge was falling apart. Ordered a rebuilt one that arrived today. Installed it after checking resistance between pins 9 and 10 (Left side) to make sure that aux. coolant pump is ok, got 26 ohms.

And now, the current wall on which I am banging my head: (all testing done by pressing defrost to get default heat and high fan)

The new (rebuilt) ACC seems to work better than the old one but only when ignition is in accessory a few seconds after glow relay goes on. When engine starts blower motor cuts out. I can put the key in accessory setting without starting the engine and play with the ACC and get all options. A/C compressor comes on, fan blows multiple speeds, defrost kicks out heat and puts fan on high. As soon as I start the car I get nothing, it's like the ACC dies. Then when I turn off car and turn to accessory I get working ACC.

Don't know if it's related but when I turn ignition to accesory. I get 6 quick flashes of the interior dome light followed by 2 steady flashes that don't stop until the car turns on. I searched high and low for what that might mean but came up dry. Seems like it's some kind of code but I have no idea what.

I also have a picture of an orphan wire that lives in the area of the monovalve and aux. coolant pump. I'll try and upload some pictures later tonight. Hopefully someone can tell me what it is/goes to/does.

Much appreciate any help that folks can send my way.