First, you need to verify refrigerant pressure is at the correct vapor pressure for the ambient temp you are in.

An R12 or R134 vapor pressure chart will give you a target pressure to test for.

IF, AND ONLY IF, pressure is equal or above the chart for the ambient temp, it is safe to jump the pressure switch.

Zero other reason to jump the switch.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!