I disagree on the "default" mode of the monovalve. Mine had a small tear in the rubber and I got very little heat. I replaced the center core and then I got all the heat I could want. I my case the default was not enough heat, not too much heat. If you bypassed the monovalve by connecting the two hoses around it you can probably eliminate it as a cause. If you "bypassed" it by opening the valve with a direct wiring then you still haven't ruled the monovalve out as a potential source of your problem. The aux pump is really only supposed to be necessary at lower RPM (but if you like heat in stop and go traffic it's a worthwhile assist). If you are not getting heat at highway speed it's more likely the monovalve or CCU.

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold