[swissarmychainsaw]

Originally Posted by hatzie

You could get a crimp in pressure switch fitting and install in the hose right off the compressor head.

The compressor head fittings, be it a Sanden or one of the Harrison units, can be acquired with an HPCO threaded switch fitting... and even both LPCO & HPCO threaded switch fittings.

Like this?
https://www.summitracing.com/parts/vta-24678-vus

So is the Low pressure switch a "binary" and the high pressure "trinary"?

Edit: Found this on "trinary switch" -- If you need to trigger an electric fan, use one!
https://www.youtube.com/watch?v=l604JCZx_ow