A/C compressor only turns on when hot?

[ericem]

Hey guys, is there a sensor that won't allow the a/c compressor to turn on when its cold outside? When it rains I want the a/c to turn on for defrost. On warm, hot days it always works though perfectly, and freezing cold.

 

Maybe I didn't fill up the a/c fully? My dad was asking me for a a/c diagram showing what electrical sensors and switches there are that can disable the a/c.

 

Also consider when I push the a/c button when it doesn't works the fans are not turning on so I don't think its the pressure switch tripping.

 

It's a 94 legacy turbo btw and uses r134a refrigerant.

[lmdew]

Low charge I'd say. Pull the pressure switch off the dryer and jump the pins. If the AC works now, its a low charge.

[Rooster2]

Don't know specific to Subaru, but some auto A/C systems are designed so the compressor won't activate when outside temperature is below 55 degrees.

[OB99W]

Low charge I'd say. [...]

Certainly possible. When it's sufficiently warm, the refrigerant expands somewhat and the pressure increases enough to close the switch.

[Fairtax4me]

Low charge.