2002 Toyota Tazz A/C completely dead

Hi Guys, I have multiple problems on my a/c. I have a a 2002 Toyota Tazz 130 2E motor, with an aftermarket a/c. I have tried 2 auto electrician who cant point out the exact problem.
Blower works in car and condenser fan engages.
1: I cant seem to track which fuse controls the system.
2: Dash switch light does not come on when pressed in. (Illuminates with headlights turned on.
3: Pressure switch is a 4 wire (why 4) I cant test across the switch due to angle and location. Switch has 2 lives coming in, 1 pair heads back to cabin and other pair heads to harness near batt.
4: I have switched relays. All stays the same.
5: Clutch not clicking in from switch. Added a test cable from batt and it engages, but system not cooling.

Could anyone suggest where and how to test each component to eliminate possible problems.

First auto elec suggested could be pressure switch but could not be sure.

Second got system activated (light on switch and compressor running but apparently only cooling to 25C/77F. An hour later I switched on the unit and light did not come on again.

My face feels like it is gonna melt off in this heat ha ha.