Depends on your driving. A daily driver will eventually burn up the fan. Above 30 MPH, most condenser fans turn off. A trinary switch would work. I've installed trinary switches on A/C high pressure lines. Unfortunately, our E53s don't have a shrader valve port. A trinary switch would simply screw on.

Does anyone know how the pressure switch works? You could grab a relay signal from there.

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'06 X5 3.0i - bought @143,123 miles (12/26/20)