The cabin heater valve is wide open with no power or signal to the monovalve. Coolant isn't circulating though. I don't know what Kat's circulation tank is or what you're trying to accomplish so I can't advise you where to tap for what. Jeremy simulated the Euro REST feature in his '95 E300. I believe it circulates coolant to keep the cabin warm if you're returning to the car shortly.

Sixto
83 300SD