Installing high pressure cut off switch into the back of an OEM type A6 axial A/C compressor. The switch has two leads one of which, I assume, goes to chassis ground. Where should the second lead go? Simple problem but I don't know the answer. Thanks!

 

I believe this is pre-electronics. The old high pressure switch would have had the AC clutches power flow through the low pressure and high pressure switches. So there are normally closed switches that only open if the pressures are out of range. When the switches open that cuts the power to the clutch. You will need to verify that with a electrical diagram.