[partsman3]

Are you running an expansion valve or orifice tube? The 89 chevy had the oriface. You would normally use a accumulator, like you have, with an oriface and a filter drier with the expansion valve.

With the expansion valve system the compressor would run constantly with the valve regulating the refrigerant. With an oriface system the oriface size doesn't change, the pressure switch regulates the flow by cycling out the comp.

I cannot see your liquid line in the pics, so I can't tell if the oriface is there. On the 89 I believe it was behind the signal light, so you would have had to add one at the evap.

That said, your switch should correct the freezing up problem. Yes, some are adjustable but they need to be adjusted correctly. Cycling too often it will not cool at higher speeds and not cycling enough will cause a freeze up. Along with other problems.

Hope this helps somewhat.