I have an 88 XJ that has been converted R-134 Ref in May of 08, I would say it was the full conversion and not just the retrofit because the compressor looks much newer than the rest of the engine. The Clutch will kick on and stay running, my high pressure sides gets very hot, the low pressure side stays where it was in temp, there is also no cold air. I thought there was a low pressure safety switch, but maybe not with the conversion done. Could it be clogged somewhere.

 

One more thing I can see in the sight glass, and it does look like there is ref moving.

 

Sounds like a clogged orifice tube,in jeeps its built into the a/c line. Condenser fan should be coming on also,this could cause high side psi.