It will if you order it that way, otherwise it will just be a binary to trip the compressor clutch. That assumes you are running a mechanical fan.

So what's the trinary switch do that the binary switch doesn't?

I'm an a/c noob. :P

The binary is only to cycle the a/c clutch. It screws into the drier unit and if the pressure gets too low it will kick the clutch out.

The TRINARY does that...plus it will complete a ground loop to you fan relay when the a/c head pressure gets to 250kpa (don't quote me on that number).

That way, your electric fan does NOT run when you are going down the highway just because the a/c is on. It will only cycle the fan when it is needed.

If you don't have an electric fan on your radiator then you don't need the Trinary switch.