Chrysler Repair: 2006 Dodge Strattus SXT 2.4L - A/C clutch not engaging, pressure transducer, dodge stratus

Question
Hello Roland,
I have already asked this question of Kevin, but he does not know what to tell me, so I figured I would see if you may be able to help me.
The following is a question and answer from this site in 2006', that was, at that time, asked of Doug Moseley.
My question will follow after, so please bear with me, as I'm at a loss for ideas, other than to tear it apart...
Question To: Doug Moseley - 8/26/2006
Mr.Moseley, I have a 1996 dodge stratus w/ 2.0 5spd w/ A/C that will not operate, the A/C light on the hvac control module does not light and the comp is not getting power to it, I checked the pressure transducer pins for damage and checked all the fuses and grounds as per the service manual? need help...  Thank you sir  

Answer
The power for the clutch should come directly from fuse 19 (40amp) in the power distribution center (PDC) under the hood.  Power should always be there at the fuse.  The source for that fuse also feeds the ignition switch so if the power source PRIOR to the fuse is bad then your ignition switch wouldn't work properly.

The clutch grounds through the clutch and power to the clutch itself is fed from the a/c relay.  Now, if the computer doesn't tell the relay to work then the relay will not complete it's circuit and power will never be sent to the compressor.  

What you'll have to do is pull out the a/c clutch relay and verify that two circuits in there have power.  If you look at the relay you'll see markings showing pins 30 and 87.  If you jump the corresponding pins in the slot the relay came out of you should hear the a/c clutch engage and disengage.

Now... the second power I was talking about where you pulled out the relay comes from fuse 9 (10amp) in the PDC as well.  If you don't have two powers in there then you've got a bad fuse or an open wire.  If you've got two hot wires and the compressor clicks on and off then for some reason the computer is not commanding the compressor on.

This can be caused by a bad control head, a bad transducer or even a sensor that measures the temperature of the component inside the dash.  The transducer connector should have three wires.  One is a ground, one is a reference voltage (5 or 8) and the other is a signal.  You can verify the reference voltage and ground but the signal is going to real difficult to take.

Let me know how much of that helped, what results you've found after checking those things above and we'll see if we can go to the next step.
Doug

Now, this is my question:
I have a similar a/c problem as the other gentleman who's question you answered not too long ago, so I followed your advice an d started checking for voltage at the relay and pressure sensor lead...
I found that there was voltage at the two positions for the relay and I was able to read voltage for the reference (4.9v) and the sensor (6.7-6.9mv) but I could not obtain any reading for continuity with the ground. could this be what is keeping the clutch from closing?
The blower motor turns on, at all levels, the control still changes all of the floor/vent/defrost options and it will still produce heat through the blower system and even when I jumped the compressor clutch at the relay slots, it still produced cold air..
I am a little perplexed right now, especially since I have been working on vehicles all of my life, but I'm not a vehicle a/c - heating system guy and would just like a little professional guidance, as I do not have the money to bring it in for a diagnosis or repairs.
Please help? you are pretty much, my last hope before I have to start tearing it apart and testing everything from beginning to end.
Thank You So Much!

Thank You Roland for taking the time to look at this, I really appreciate it!


Answer
Hi Ron,
The pressure transducer (sensor) voltage (6.7-6.9 mV) is one reason why the compressor will not be activated. That voltage indicates too low a charge of refrigerant in the system. For the pcm to activate the clutch relay that voltage has to be in the range of 0.451V and 4.519V. Above 4.519V means the pressure in the system is too high for safe operation and that will defeat the relay also. So either you are low on refrigerant or the transducer in inaccurate.
You mentioned the pressure sensor ground possibly not being connected, which could also cause this low volage reading. The black/light blue ground wire from pin 1 of the transducee plug is connected to pin 27 of the black/orange plug at the pcm. So check out that connection.
Let me know if that isn't the answer.
Roland