compressor will not engage, It has manual controls so I cant see any data. replaced the evap temp switch, control head, pcm. I am able to ground the control terminal of the relay and activate the clutch. I have signal to the cluster from the control head Butcant tell if im getting anything from the cluster to the pcm. the signal goes to can bus between the ipc and pcm. there is also a u1900 set in the ipc, ive checked the communication wires between thw ipc and pcm for continuity .2 ohm. anyone seen this before. thinking cluster, but want to be sure.

 

Have you verified that the system has a full charge of R-134a in it?. Don't see you mentioning anything about pressure reading. What is your pressure readings of the system? With a full charge, your static pressure reading will vary based on the ambient temperature at the time of the reading.