I have a 2000 Dodge Dakota with the 3.9L 6 cylinder. Starting late last summer I noticed the A/C becoming less cool. This summer it is worse. I bought a can of Sub Zero R134A recharge with the pressure guage. Followed the directions on the can to test the pressure and recharge. Hooked it up to the low pressure port while the engine was running and A/C on full blast. The pressure initially was in the good range (around 50psi) but then you hear a click from the compressor and the pressure dropped to 10-20PSI for about 10 seconds then another click and the pressure jumps back to 50psi for a few seconds, then another click and drops again and so forth. This continues as long as I watched it (~3 minutes). I then tried adding some R134A. The readings went up slightly but you still see the pressure dropping and jumping along with a clicking noise. Is this the compressor turning off/on and if so does this mean my compressor is shot? Any suggestions?