97 Supreme A/C Clutch problems

Last year 07 I was able to short the low pressure sensor and activate the clutch so I could add freon. This year I did the same thing but the clutch wound not engage. I check the obivous fuses and all are good. The panel switches seem to be working OK. It's has the automatic air settings. IE you have to turn down the temp setting on dash panel

Also the "check engine" light comes on & off occiasionaly.

Everything else in the car works great

Any Idea's

Don't be "shorting" three wire "switches" they are actually pressure transducers- that feed back exact pressure readings to the ECM- you risk frying your computer - if and when you add refrigerant- the pressure when it reaches 47 psi will automatically engage the compressor-- you must have a leak- most likely place is the compressor shaft seal and the compressor case halves-- Good Luck!