You not only need gages to check what the static pressure is, hi=lo=ambient air temp, first thing in the morning before the car is started....so if the air temp is 70F, pressure should be 70 PSI.....if much lower, you have a refrigerant level problem.
If gage pressure looks ok, then you need a scan tool to read data to the PCM....this system uses a 3 wire pressure sensor(which can't be jumped like the old pressure cycling switch)......the sensor should be giving the SAME PRESSURE INFO AS THE GAGES........if it is giving too low or too high a pressure, the compressor will not run..........