Now that cold weather as set in I've been chasing a gremlin in the
climate control.
First this 90's wagon has manual fan speed/vent control with dual
temp controls.
It slowly cycles between blowing mid temp, to hot, then to cold when
you've set things to say 20c
I replaced the interior temp sensor, but testing of the old one seems
to show it's ok anyway
and the behaviour did not change.
At the duo-valve assembly, I cleaned the contacts and I know that if
it's disconnected that I get heat even if dials are set to min cold.
Plugging in the circuits gives me hot at max, and cold at min. Ohms
across the valves gives zero. So I assume the valves mostly close
otherwise I would not get cold air on both sides.
My cheap digital multi-meter won't show voltage cycling, but I get
12.75 on heat, and 13.5ish on cold on both sides of the plug
(3 prong, assuming center plug is ground).
So does this imply the push button unit is bad?
Thoughts are welcome.
John
1983 300TDt 358k Kilometers (mobil 1 Delvac)
1990 300TDt 152k Kilometers (mobil 1 Delvac)
1993 500SEL 168k Kilometers (mobil 1 0w40)
