Help with subaru trinary switch / ac pressure switch

Hello,

My mechanic says that my 1993 Subaru Legacy Wagon (has 2.2 liter boxer engine, auto trans.) needs a new “AC Trinary Switch” for the air conditioner to work, but he cannot find the part anywhere. I’ve had a hard time finding one too!

This part may also be called an AC Pressure Switch, or a combo of names like Trinary Pressure Switch.

I do not know the part number for sure, but the part is located on the passenger side of the engine bay, plugged in near the condensor. It is a round plug with four wires.

If you have any knowledge about a good place to look for this part or how i can find it, much appreciated…