Well everyone seems to agree that I should check the monovalve.
Something happened this morning that makes me wonder what the heck is
going on. This morning, I had heat. I had it set on the regular
non/ac vent mode. About half way to work, I noticed I was warm and
that
warm air was coming out the defrost. I did not have the defrost on.
After a little while, I was too warm, so I turned the temperature down
and it got colder and switched from defrost to vent.
Changes to the venting have _nothing_ to do with the monovalve,
only the control unit (embedded in the pushbutton array). How are
the fuses feeding it? When deprived of power or vacuum, the system
reverts to defrost-pattern heating. The monovalve is merely what
controls if the system will heat or not, under command of the ACC
brain.
But you still _should_ check your monovalve. It's easy, and is
a wear item that is often broken. (Torn rubber diaphragm.)
-- Jim
