I know this has been discussed in other posts but nothing I've tried so far works. All functions of the ccu appear to work except for the heat functionality of the climate control. So far I have replaced components of the mono valve and it seems to be functioning as I understand it's supposed to work i.e. the plunger and diaphragm move in and out to control coolant flow to control temp. The Aux pump is operable and has flow. I have raised the vehicle on a jack while on a steep hill and filled coolant through the top rad hose to thermostat housing while at op temp so I know the coolant system is full, I have also replace the ccu with a junk year unit and it seems to not have made any difference to the original unit ( which I took apart and inspected for broken solder traces) Is there a step I'm missing. Any help would.be great thank you.