Well once you have determined that water flow is your problem then WHY is the water flowing? DO you have monovalve electric control? If not then why not. If so then why doesn't the valve close?
If your control isn't appropriate then I would evaluate the temp sensors and temp wheel values at the controller. We have a MB climate control tester for those old guys but we always diagnose by symptom and function evaluation; mostly from the wiring diagram. BTW be sure the aspirator hose is fully attached to the in car sensor. No air flow will mess with control.
[This message has been edited by stevebfl (edited 06-29-2000).]