Soo at this point I am stumped on my AC unit, 04 matrix XR, originally across the relay switch that sends power to the compressor was at 5 volts, did some digging around, pressure switch is good, ohm'd out the electrical coil in the compressor, came up open, no resistance. Switch on dash is also good, fuse in driver kick panel is good, blower is moving air. Ordered that part new from toyota, Ohm'd that too before leaving the dealership parts, if I remember about 4-5ohms, installed it with ease, did not loose any of the washers that are with the clutch. rechecked the compressor is properly grounded. Rechecked voltage at relay, 12v, compressor clutch is engaged at this time. Let run for about 20-30 mins in idle, pressure is good, across the coil is 40'F, Las vegas ambient was about 90 with cloud cover and humid, didnt record the moisture levels. After the local driving, I was able to pull down to 54'f in the supply vent w my thermometer to measure the air temps. Fan for ac mode is running, no issues. drove around locally, light to light before heading home, normal driving, not beating on my car. As soon as I accelerated to match highway speeds, within a small distance I noticed my thermometer in the vent starting to rise in temps to ambient, which by then was closer to 100'F ambient. from then on no more cooling. Checked the fuse under the driver side kick panel, it is not popped. I have yet to re ohm out the new coil to see if it became open for some reason. I am just beat and disappointed at this time. will take a look at it again this weekend. Have any other ideas that you guys can suggest or know something specific with the matrix's ac. I herd that the relay is majority of the issues but not this time. I am not sure where else to look. Help a fellow new matrix owner. Thank you guys