Entrophy with trinary

[blitzer454]

How long are you waiting for the fan to start after turning on the A/C? I know on my car it can sometimes take a couple of minutes before the trinary switch turns on. You could also try measuring the line pressure with a manifold gauge and confirm the pressure gets above 254psi. If it does then I would say the switch is bad given that the fan does run if you manually ground the Entropy fan wire, assuming you were grounding it from the same ground the trinary switch uses.