I have a 1988 Chevy K1500, 350 eng, automatic. The compressor clutch bearing failed so due to 220k miles I decided to replace R4 compressor, accumulator, and orifice tube. My problem is the new R4 compressor came without the cutout switch installed. The old compressor had a single wire yellow connector. My parts supplier has ordered 3 times what says to be a single wire yellow conn but he gets a two pin green instead.

I can't find any information about pressure switches and their color codes anywhere. The system will be retrofitted with R-134a so can I use a different switch that would work with the different pressures?