Problem of the Day: air conditioner

[Benjamin Weste Pearre]

1990 200 TQA:

Next problem: it's getting hot in Boulder.  I was driving a couple of
days ago, and had the AC on.  It was working one minute (unless that
was just cold air in the system from overnight...), and then started
spitting out warm air.  Also, when the AC is on, usually the car has
very noticeably less power.  Now, I don't feel that.

The Bentley diagnostics (both channels 17 and 18) claim that the
compressor is on, but that should sap power, and it isn't.  I don't
want to go digging around without some clue about this -- will both
channels 17 and 18 say the compressor is on when, say, the AC clutch
is broken?  Any other likely problems?

Also, where is the AC wiring harness in which I'm supposed to be
measuring control voltages?  Do I have to remove the climate control
head?

Thanks in advance!
-Ben

--
Ben Pearre          1990 200TQA          http://hebb.mit.edu/~ben