1998 Plymouth Voyager A/C Clutch will not engage

My 98 Plymouth Gran Voyager A/C clutch will not engage. The system has adequate refergerant. Trouble shooting has revealed that the A/C clutch relay solenoid does not have a ground. The Plymouth service manual states that the PCM operates the clutch relay ground circuit. I am assuming that i need to replace the PCM, but before I buy one I would like to have a second opinion that it is the PCM.

Thanks,
James Gorman