Follow the small rubber hose from the mono valve to the inner bulkhead = this connects directly to the windshield heater valve.
I will try to get pictures today.
Must take daughter sledding NOW or suffer her wrath.

Yep, thanks again, Craig. The diagram is very helpful. I had a Ford POS (EXP) that had a heater core leak. It's restrictor valve was at the H/C inlet, so summer driving did not reveal any problem. It was the winter when I noticed the H/C was gone. At least it was easy to change, remove the coolant hoses, remove the glove compartment, remove the H/C cover, and pull out the H/C.

I would use the ballcock fix as a "stuck on the road" fix instead of a permanent one.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Pictures attached.
Follow the small rubber hose from the mono valve to the inner bulkhead = this connects directly to the windshield heater valve.

Attached Thumbnails

   

Here are plans and pictures of how to change a mono valve system changed to a vacuum controlled system:

Mono Valve Voltages