Put on a new a/c compressor the clutch will not engage

You most likely need a new ac compressor

yes there is low pressure cycling switch on low side
bypass those wire and if the clutch engage then your low in freon or switch defect

1) TEST the fuse+ relar of a/c
see the next steps and fix it. God bless you
If so, the compressor is working and the A/C system probably contains enough refrigerant to make cold air, so the problem is inside the HVAC unit. Replace the motor that controls the blend air door (this is a difficult job and best left to a professional since it involves tearing apart the HVAC unit -- about an 8 to 10 hour job!).
If the compressor does not engage when you turn on the A/C, see if it will run by jumping the compressor clutch wire directly to the battery (use a fused jumper wire). If the compressor works when you jump it, and the A/C blows cold air, the system contains refrigerant and the fault is likely a bad A/C compressor clutch relay or a bad clutch cycling switch or pressure switch.
If the compressor does not engage when you jump it, the problem is a bad compressor clutch.
If the clutch engages but the compressor does not turn (the belt will start to slip and squeal), the compressor is locked up and you need a new compressor.
If the compressor clutch engages and turns the compressor, but the A/C still does not blow cold air, the system is probably low on refrigerant and needs to be recharged

proceed according and fix it. God bless you
If so, the compressor is working and the A/C system probably contains enough refrigerant to make cold air, so the problem is inside the HVAC unit. Replace the motor that controls the blend air door (this is a difficult job and best left to a professional since it involves tearing apart the HVAC unit -- about an 8 to 10 hour job!).
If the compressor does not engage when you turn on the A/C, see if it will run by jumping the compressor clutch wire directly to the battery (use a fused jumper wire). If the compressor works when you jump it, and the A/C blows cold air, the system contains refrigerant and the fault is likely a bad A/C compressor clutch relay or a bad clutch cycling switch or pressure switch.
If the compressor does not engage when you jump it, the problem is a bad compressor clutch.
If the clutch engages but the compressor does not turn (the belt will start to slip and squeal), the compressor is locked up and you need a new compressor.
If the compressor clutch engages and turns the compressor, but the A/C still does not blow cold air, the system is probably low on refrigerant and needs to be recharged

see this steps and think with clearly and logically NOT feared. God bless you
Start with the compressor. Does it engage when you turn on the A/C?
If so, the compressor is working and the A/C system probably contains enough refrigerant to make cold air, so the problem is inside the HVAC unit. Replace the motor that controls the blend air door (this is a difficult job and best left to a professional since it involves tearing apart the HVAC unit -- about an 8 to 10 hour job!).
If the compressor does not engage when you turn on the A/C, see if it will run by jumping the compressor clutch wire directly to the battery (use a fused jumper wire). If the compressor works when you jump it, and the A/C blows cold air, the system contains refrigerant and the fault is likely a bad A/C compressor clutch relay or a bad clutch cycling switch or pressure switch.
If the compressor does not engage when you jump it, the problem is a bad compressor clutch.
If the clutch engages but the compressor does not turn (the belt will start to slip and squeal), the compressor is locked up and you need a new compressor.
If the compressor clutch engages and turns the compressor, but the A/C still does not blow cold air, the system is probably low on refrigerant and needs to be recharged.

When you changed the compressor, did you recharge the AC system? If the pressure switches are not actuated by the correct pressure, the system will not engage the clutch. To charge the system you have to pump a vacuum on the system for about an hour. Follow the new compressor instructions as to the amount of oil that may be in it and how much the system calls for. See it has the correct type oil and the correct amount, then charge with the correct refridgerant and the correct amount.

Gaker

If you have already checked pressure or put in a can of freon, then it could be the compressor clutch is bad or is not being energized.
Check for voltage at the wire to the compressor clutch, and that the compressor is properly grounded.
If you want to by pass the relay and control for the relay, just power the clutch wire with a jumper. You should see the center of the compressor hub start to spin along with the rim of the pulley.

Locate wires coming from compressor clutch and trace to nearest plug that you can unplug. Turn on A/C to max cooling. If clutch not engaged (center of compressor drive pulley not spinning with pulley), unplug compressor clutch wires and use multimeter to check voltage going to compressor clutch. If voltage is around 12 volts or more, then clutch should be engaged when plugged in. Plug clutch wires back in (with motor still running and ac set to max). If clutch still not engaged, then clutch definitely bad because 12V signal should engage it.

could be low of freon ,most cars has a pressure switch so when the system has a leak and loses presure under the rated pressure of the switch it shut it off...it is located on the dryer it will be a 2 wire plug type set up, unplug the ele. plug side momentary and jump it with a jumper wire and see if you hear the compressor clutch kick in if so either the switch is bad or your system has loss freon. could be also something as simple as a blower fuse or relay too ,last but not lest the compressor clutch couldv'e gone bad. to ck that if you are getting fire at that pressure switch and down to the compressor then the clutch is bad or compressor as a whole has locked up but that would make it either throw a belt or burn it off.

Try checking the spacing of the clutch of the compressor to your A/C...chances are the gap is too large and will not pull down to engage the compressor. That should eliminate the jump wire and keep your car snowing. No clutch to engage the compressor, no A/C.