Yes, try 12 V directly to clutch.
Here is a pdf of the compressor circuit:

 

Thanks for the schematic. The clutch electrical connector bracket in my car was installed pointing upward instead of downward. I can disconnect the 2-prong clutch plug at the top, but there isn't enough room to fish a 12V line with ground into from above. Having big hands doesn't help either. I'll keep trying. I have the diagrams from a download from a link that you provided years ago... thanks.

also... JIMVW, no, there is no check engine light and the engine is operating well withing the proper temperature limits. Other than having a clutch that is not engaging, there doesn't appear to be anything else wrong with the car.

 

So what was the ambient temperature? 24 psi is below the range that you provided, and if it was warmer than 65 degrees, you're even more out of spec.

You might just be low on refrigerant.

 

You could jump the relay terminals 30 to 87.

 

Hey guys.
RJ - The ambient temp in the garage was around 55 F when I checked the pressure. My understanding is that if it is a little low on 134a, it will still click on and then start cycling on and off. The clutch is not clicking on at all. The nominal pressures for these systems vary with ambient conditions. I'll check it again when the ambient temps are higher and they should be proportional.

donbrew - I have 12V on terminal 30 and I'll jump it when I get back out there. Earlier today, I put 12V across the clutch connector and it made a healthy click which indicates that the clutch mechanism appears to be working. It is increasingly looking like a logic problem. The clutch relay (#15) checks good and it has power. It looks like the diode is functioning properly and the wiring harness to the clutch appears to be intact. The pressure sensor was by-passed and it still didn't engage (so the pressure sensor doesn't look to be the culprit). And finally, the clutch itself is engaging when voltage is applied directly. I need to check the internal fuse block (on the right of the middle console) to see if there are any fuses that may be related that are blown.

The next few days are fairly busy with other activities, so I may not be able to the play with it again until Monday.

Thanks for the advice... it's always good to have knowledgeable people to confer with.

 

The pressure sensor doesn't work that way, look at the schematic

 

It is the clutch.

Remove the wire from the clutch coil and you will read your full 12volt. You are reading .2v because the coil is shorted. You will want to borrow/buy an A/C pulley holding tool. This task can be done without removing the freon lines. It is a very difficult task. There are two different styles of compressors for this year. Good luck!

 

As I suggested in post #9. The clutch. It’s fairly easy to replace.

https://ebay.us/m/skx2KL

And not to expensive

 

Update.
1) With the engine running, I jumped terminal 30 to 87 (relay #15) in the engine fuse box and the clutch engaged with no problem and the compressor seems to be running fine.

2) I pulled the HVAC fuses from the inner fuse panel and all of the fuses were good.

3) The pressure sensor has three lines (5V reference, low voltage and the sensor reading). I jumped the 5V reference line to the sensor reading line which (I think) should tell the computer that the pressure is within nominal limits... Is that wrong?

It looks like the "AC on" signal from the ECM is not getting to the clutch relay What else can I check before I look into replacing the ECM?

Thanks!

 

Additional Update:
After further investigation, I found that the 5v line is for the high pressure condition. The voltage passed through the sensor is determined by the pressure read with the 5V signal being the highest setting. Normal operating voltages should be between 0 volts and 5 volts. Is there an easy way to accurately determine if the sensor is working properly without breaking the system open?