Chrysler Repair: A/C clutch not engaging, pressure transducer, car wont start

Question
Hi Roland, I just bought a 96 Concorde with a 3.3 in it.  The A/C  clutch will not engage.  I thought it was low on refrigerant so i bought a couple cans of 134 and it actually wound up taking almost 3 full cans to fill it.  The a/c clutch still wont engage.  If you take the connector off the sensor in the condenser line and try and cross the terminals to get the clutch to engage( I needed to try and do this to get the refrigerant in the compressor) the car wont start at all.  If you pull the relay out and cross two of the terminals in there the compressor fires up the clutch engages and blows ice cold air......what am I missing here?  Is this a sensor problem somewhere or is it a wiring problem.  the relay is good, and all the fuses are good.  Thanks for your time.

Answer
Hi Gregg,
You could check the dark blue/orange wire at the relay socket (pin C which is the one at the passenger side of the relay) to check whether the engine controller (at its pin 34) is giving the signal to close the relay or not when you ask for AC. It should show 12V on it when engine running but no AC requested, and then should be grounded when you ask for AC. If it doesn't ground out then check between C and 34 for patency. It you have that, then the controller is not getting the "word" from the pressure transducer that it is OK to fire up the compressor. The transducer has 3 wires: violet/white with 5V on it, black/light blue a sensor ground, and dark blue which is the signal as to the pressure level. I don't know for sure what the sensor signal reads when it is OK to fire up. But it may just be that the transducer is not reading the pressure correctly and needs to be replaced. Its violet/white wire goes to pin 6, its dark blue goes to pin 48, and its black/light blue goes to pin 4, all at the engine computer. So you could check the wiring to it as well.
It is delicate so that it could be damaged. Use a new O-ring seal and tighten to 50 inch-pounds. You may note a slight release of pressure when you remove it but don't worry. The system will not need to be emptied or refilled due to changing this sensor, according to the manual. The system holds 28 oz of R-134a.
Please let me know what you learn.
Roland