Which pins are shorted on AC pressure switch to get the AC compressor to cycle to fill unit with freon?

if on and off consistently [short cycling ] the usual cause is low or short on freon others are low pressure sensor switch -or clutch failing but the usual problem is freon level

is the compressor coming on

If the compressor wOnt cycle, it means that the pressure is not correct. How much freon, (and what type) did you put in, and did you PULL DOWN (with vacuum) the system to about -29 inches before putting the freon in? Did you use manifold gauges? If so, what is the high pressure, and what is the low pressure, at what ambient temperature?

probably to much Freon! when adding Freon always put a/c to its coldest setting and make sure its on max!

Depending on how much freon is in the system, it could be a faulty low pressure switch or a faulty clutch.
You would jumper the low pressure switch to eliminate it for a test.

The pressure switch is right next to the battery negative terminal. To bypass the switch, remove the connector and use a paperclip to jump the terminals inside the connector. By the way, you need to put oil in the system, or the seals will quickly dry out.

sorry it has a leak ,only way to fine it is to use the correct machine and vacumn it out ,then turn machine off and listen for a sucking sound ,most likely cause is the flexible hoses/compression fittings or the seal on the front of the AC compressor ,if you still cannot find the leak then fill AC with a special dye and use a ultra violet light and yellow glasses to find the leak .

Have a code reader or scanner put on the car to erase all codes,this should reset the ac system circuit.Also check the low side clutch cycle switch,it may be the problem.

Running a hot wire bypasses any compressor cycling. Low side should pull down to 20 psi or less when compressor is hot wired. If not pulling down you may have weak compressor or way to much freon in system.

the magnetic clutch used to drive the compressor might have a short.