Good morning,

Where does the auxiliary fan get its signal. Appears to be from the high pressure switch. I don't see a switch on the radiator or head. I know the later models with two speed fans,(ala BMW) get the signal from the compressor lead and run in low whenever the A/C is on and switch on the radiator to engage high speed when coolant hits a spec'd temperature.

I don't want to get the head pressure to 290-300psi to test it if not absolutely necessary. No point in straining an older system unnecessarily.

It's still running R12 so I don'r want to evacuate the system unnecessarily either.

Tony