2002 Outback VDC A/C problem

[Mike (archive)]

To All,

A/C compressor sometimes engages - sometimes not. I can force it on at the relay and the A/C works fine (nice and cold). I have traced that the relay control - which switches the ground to pop it on or off
- is loosing it ground contact (the +12v is still there). What controls this ground switching? I don't know if it's turning off due to a bad connection or it's doing it because it thinks something is wrong with the system.

Mike

 

[CompUser]

A/C compressor sometimes engages - sometimes not. I can force it on at the relay and the A/C works fine (nice and cold). I have traced that the relay control - which switches the ground to pop it on or off
- is loosing it ground contact (the +12v is still there). What controls this ground switching? I don't know if it's turning off due to a bad connection or it's doing it because it thinks something is wrong with the system.

I don't know if this will help you or not, but
working on my 04 WRX, I discovered that Subaru
uses *the ground* to control panel illumination
intensity. In other words, where most (all that
I've ever encountered) other makers control panel
brightness by modulating the + voltage, Subaru
has full + voltage applied at all times and
instead modulates resistance thru the lamps, to
ground. It works, but it's "weird".

If this is something they do with other circuits,
including your AC control, this might help your
troubleshooting.

Steve

 

[JCee]

There is a bulletin concerning the A/C revolution sensor and it sounds like you may be experiencing this here. The sensor is located on the back bottom of the compressor. I think you may need to remove the compressor to replace the sensor. Hope this helps.