A/C finally working

[treed2 at wsu.edu (T. Reed)]

Okay, so it wasn't my expansion valve or anything in the sealed system. It 
turns out that I have haunted wiring going to the A/C clutch. I'm really 
happy about this because I was dreading having to do rent the vacuum pump 
and do everything over again.

The clutch was engaging when jumpered but when I would start to drive 
somewhere it would immediately disengage due to vibration or movement or 
something (it's not clear exactly what). I finally observed this today 
when checking the electrical side of things again. I pulled the alternator 
to get better access to the clutch connector on top of the compressor and 
disassembled it, cleaned it and tested things. After cleaning the nasty 
corrosion build-up off of the connector, it seems to work a little 
better.. but all is not fixed.

I jumpered the clutch directly to the battery again and drove around. 
Finally!! Cool air is blowing from the vents. My low side pressure is 45 
psi with a 90 degree ambient temperature (it gets 'cold' at night). It 
seems that last time I checked pressures I was reading the gauge scale 
wrong and it was actually ~110 psi static pressure, not 300. I feel like 
an idiot for not noticing that the high and low side gauges have different 
scales, but I'm also relieved that the pressure is not really that high.

With the blower running and the HVAC controls on A/C, I'm getting 11.8 
volts or something close to that at the low pressure switch (either 
terminal), but this isn't enough to actuate the clutch. There's too much 
resistance in the wire.. the voltage drops to 4.1 volts when I connect the 
clutch. So I have a partial break or some kind of damage to the wire (or 
more badly-corroded connectors in line with it). There isn't even enough 
current to trigger a relay. I was planning to just relay the compressor 
clutch to solve this issue. Nope..

Anyway, I'll have to try to track the wire back up inside the dash and 
find the bad connection, or something. The Bentley has a rather poor 
electrical diagram for the A/C since it's not 16v specific and it is 
missing connectors and seems to have some other errors. So I get to tear 
my dash apart looking for things. Fun.

Thanks to those of you that offered help or advice.. A/C is not 'optional' 
where I live, and it's going to be great to have the freedom to drive 
places during the day instead of just morning/evening/night when it's 
a little cooler.

-Toby