Before we start, if anyone needs AC work; message me. I've torn my car down and surprisingly these cars are really simple. I would be happy to guide you through any process and share my tips and tricks for free.

Now...

1. Has anyone installed a needle valve between the accumulator and the AC HP Cutoff Switch aka Clutch Cycling Switch that you can close allowing you to change the switch without evacuating your AC system?
2. Or has anyone found a "T" fitting you can install with a pressure switch on each end in case one goes out, you can plug into the second one, again, so you don't have to evacuate the system?
3. If you've changed your HP switch/ compressor cycling switch, what brand have you found is the best.

My thesis below is the story of how I came to these ideas.

2004 Limited (Non-SRT). I recently had my AC give up the ghost. Troubleshooting revealed a worn Compressor Clutch. With 115K miles on the original system, I decided to pull it all out, inspect and flush it, and replace the "typical" parts. Those parts included the compressor, condenser, accumulator (drier), orifice valve, HP Switch, and flushing the hoses and evaporator. The system was surprisingly clean with no evidence of "The Black Death".
Rock Auto (see Lessons Learned) provided the parts, and I provided the labor. Per the Shop Manual, weighed and added 4.4fl.oz. PAG-100 into the compressor fill port, and setup to add 197lbs. (31.52oz.) of R134a.
I got the system back together, car at running temp, my shop fan blowing across the condenser, windows down, and while charging the system was reading pressures at idle and 1500 RPMs.
My pressure(s) math at 87dF and 70% humidity, at 1500 LS should be 45-55psi, and (taking into account humidity and equation of HS= Amb x (2.2 , 2.5) HS 200-230

While charging, I began to hear a faint "knocking" sound coming and going. I also noticed that as I approached 220psi on the high side, the compressor clutch remained engaged.
With the unit charged, my pressures were good, but the compressor was still running, so I performed a continuity check and sure enough, the NEW HP switch was bad.
I checked my pressures at steady state, and they were within 1psi of each other, so the charging process was not the culprit.

With the system evacuated, I dropped the compressor, and found the clutch had about 1/4" free movement before you could feel the primary shaft turn.
Now I'm no dummy. Grew up poor so when things broke, went to the library or the Chilton's Manual and fixed it ourselves. Learned to weld at 12, and began fabricating, painting, and building hot rods at 13.
I'm a Rotating Equipment Engineer specializing in gas and steam turbines, and gas compressors. I feel pretty confident in my abilities to troubleshoot and repair, and I know there should NEVER be slack in the clutch!

I took the rebuilt "alleged" Nippondenso compressor to Compressor Warehouse here in Houston. Used them for years but totally forgot about them because I haven't had to perform AC work in years.
The team at Compressor Warehouse knows AC and as I expected, the slack in the clutch was cause of the knocking heard while running.

So, the team at Compressor Warehouse rebuilt me another compressor that day and since I found no evidence of internal mechanical failure (FOD or shavings), I completely disassembled it all again, flushed everything minus the condenser, installed a new accumulator and HP Pressure Switch.

I've got it all together now and it's waiting to pull vacuum and recharge, but although the NEW pressure switch is "allegedly" better than the first based on reviews; I know people are paid for reviews and I just can't get myself to trust it knowing I could have to pull it all apart again.

LESSONS LEARNED...

• Unlike the past, you are blindly tossing darts when you buy parts today.
• Rock Auto sells junk, and their return policy is also junk. There's a reason their prices are so good because you get what you pay for, but in their case, you can't get your money back!
• The compressor came from GPD (Global Parts Direct), will only buy from Compressor Warehouse.
• The HP switch was supplied by UAC, won't suggest using them either.
• The AC system on these great little cars is simple to work on as long as you have a decent set of TORX and e-TORX sockets.