Why won't my air conditioner work?

unplug the low pressure switch in the air conditioner line near the dryer with air switched on , jump the connector with a short piece of wire to see if the compressor clutch engages. If it does your pressure switch is bad. If the pressure switch is good then there is a fuse near the compressor somewhere that may be blown. If it blows new fuse your clutch is bad.

Kelly,Trouble shooting forum links below, the 3rd video show which contacts to cross to get AC clutch to engage.
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Honda Odyssey not working
Compressor Clutch won engage Honda Tech
Troubleshooting AC unit Honda Odyssey 2003

Looks like you checked all the things that need to be checked except "one." Sounds stupid, but did you check your temp switch on you dash to make sure it is the air conditioner you want to run instead of the heater? Sometimes, many forget this one simple check and can't figure out why the air conditioner won't engage.

1992 Buick PA,if you add power directly to the clutch and it comes only obviuosly you have a power supply problem or low freon,Your system basically has a low pressure switch this is located on or near the filter drier,if you jump the switch together,you have low freon or a bad low pressure switch,

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.

Sounds like either the air gap between the a/c clutch and the pulley is to far..Or the clutch itself is bad..You can remove the bolt in the middle of the clutch,,Work the face of the clutch off,,and take out the washer..If there is 2 washers then remove one of them,,and reinstall..If there is only one ,,try it with no washer...The washer adjusts the air gap

the ECM supplies the ground circuit for the a/c clutch. the high pressure switch also needs to be closed to engage the clutch. when the low pressure switch and the high pressure switch are closed that completes the power circuit to trigger the relay.then the power on the #30 terminal can connect to the #87 terminal to send power to the a/c clutch.

I have the same problem right now, and from what I can figure, it looks like an intermittent thermal protector switch on top of the AC compressor. My 2003 Civic air conditioning works fine for 20 minutes or so and then stops working. If this switch is faulty, the compressor clutch won't engage and you won`t get cold air. I will get it replaced soon, but it seems like the access is not easy.

The low pressure switch turns on appox 26 psi. If the pressure is lower than that, it wont work, you have a leak.

Check for a fuse that indicates radio and replace it if it's burnt through or melted or discolored. The Buicks have dash controls that require expensive repairs sometimes to get the temperature controls to work so some people jump around the controls by installing a separate toggle switch that directly turns the AC unit off and on for 92 through 94 Buicks. Any AC shop can install the bypass wires.