Robie,

Cut the front of the case straight down from the bottom of the heat duct to
the floor on both sides.  This will remove a small piece of the housing. I
used a loose hacksaw blade.

The valve turns the water flow off and on.  Easy to determine which way is
off or on.

My question about the rear heater involves how the fan is supposed to
receive an air supply from a closed box.  The gap around the valve is big
enough to provide much air flow.

Removing the small piece of housing in the front probably helps.

Randy Herd
86 GL Weekender
68 Kombi
98 Jeep Cherokee

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