R4 Compressor Cycling Issues

[84 Silverado]

Team,
Working on my 84' AC system. I filled the system with (AC Pro purchased at Orileys) 134A. Once the guage was in the green (see pics) the compressor cycles on and off very quickly when the Low pressure switch is wired up (see pics). When I bypass the switch (see pics) the compressor stays engaged.
The low pressure switch is brand new (see pic). I know very little about AC systems, and I'm obviously missing something here.
Any help would be appreciated.

Thanks in advance.

 

[bucket]

Three things:

1: Don't ever use that AC Pro garbage. ONLY use refrigerant that does not include stop-leak.

2: The pressure gauge is ONLY useful when the compressor is active. It basically means nothing when the compressor is not running.

3: Ditch those wire nuts.

 

[fast 99]

Generally rapid cycling is caused by low pressure on the suction side.