Chrysler Repair: 97 grand voyager ac and recirc flashing...no A/C, positive temperature coefficient, digital voltmeter

Question
the title says it all, what may be an issue is the following: I got a new very fancy stereo system for x-Xmas, installed and all was fine, when I went to use the a/c a couple of months later it didn't work. about then I noticed the a/c button and recirc button flashing. they go out after a long time, but still no a/c. refilled the freon with the dye but no leaks. replaced the compressor about 3 years ago.

also noticed that the a/c clutch does not engage, tried replacing the ac relay in outside fuse box to no avail.

also note I replaced the main computer next to the outside fuse box 3 years ago.

any ideas would be most appreciated...
Thanks,
Russ

Answer
Hi Russ,
Those two light flashing just means that the AC is not cooling down the system as it should, which of course you know already. I would focus upon getting the compressor restarted. Check the leftmost Positive temperature coefficient device (the #1 fuse-like device in the row that is just below the four plugs in the fuse box under the dash) and check the fuse #11 in the power distribution box under the hood (15 amp) looking both for a blow out and a subtle crack in the internal wire. The compressor should operate unless you either have too low pressure of refrigerant or the pressure transducer switch for the system is inaccurate. If you know by independent gauge reading that the pressure is sufficient then I would consider replacing the transducer. It has three wires: a black/light blue which is the sensor ground, a violet/white which provides a 5V supply, and the signal is dark blue. With the engine idling the voltage should be .451 to 4.52V for the compressor to be activated. If it reads 0 the transducer is bad or you don't have a 5V supply.
0.15 to 0.45 means the pressure is too low, 4.52 to 4.85 means pressure is too high, 5V means transducer is bad. You can read between the ground wire and the signal wire with a digital voltmeter by using fine pins to pierce the insulation of the wires. The transducer is in the refrigerant line on the firewall on the passenger side of that panel near the alternator (3.3/3.8L engine)
Good luck on this and let me know what you find, please.
Roland
PS Once you get the compressor going then there is a way to run a self-test of the system from the control panel. See the immediately previous question and answer which will be posted by tomorrow.