Ac was working fine, blowing cold air and now it does not blow cold air. I noticed the compressor not kicking in. Put the gauges on and the low side is 10 psi and the high side is 0. I jumped the compressor so it would kick on and the low side pressure went to 0. Removed the jumper and it went back to 10 psi. The high side never moved off of 0 psi. I think it might be the expansion valve, what do you guys think. Just want to make sure before I dig into this thing. System is 134A.