MK2 A/C clutch won't engage

[sasksupra]

My air conditioner compressor clutch won't engage on my 1984 Supra. Here's what I've checked:

1. I have power at the A/C Switch (light comes on).
2. I'm only getting 0.11 volts when I check the lead at the compressor.
3. Ohms are within spec (0.37 ohms) when I checked the magnetic clutch.

According to the wiring diagram, there is a pressure switch between the A/C switch and the compressor. I'm guessing that this is the source of my electrical problem.

• Where is the pressure switch located?
• What is the purpose of this pressure switch? Does it prevent the compressor from engaging if the pressure system has leaked and is empty?
• Can I run a wire from the battery to the compressor magnetic clutch to see if it engages to verify that the magnetic clutch is OK?

Thanks

[toyomoho]

The magnetic clutch requires 12V +/- to engage. You jump the clutch wire to determine if it engages. Be sure you run down the correct wire! There might be other wires in the area going to the speed sensor (if equipped) on the compressor housing. As there may be a problem with the A/C system, do this with the engine off.

The pressure switch prevents the magnetic clutch from engaging if the system A/C system pressure is too low or high. It might be located on the top of the A/C dryer, a large cylinder most likely bolt to the front the engine compartment. Follow the hoses from the compressor to the front of the car. The switch is on/off device set to respond at a low and high pressure setting.