I'm trying to recharge the A/C. This is a system that has had new lines, 134 conversion, compressor etc. With everything hooked up and turning on the A/C I hear a click and, change in idle, fan comes on etc., but the compressor doesn't engage. I thought it was just low on freon and I guess it still could be but I'm not sure. Since the compressor wouldn't engage I bypassed the A/C clutch switch, the compressor engages, and the A/C is very cold. The pressure read low and I've added a couple of cans of 134a but the pressure doesn't change and stays right at 25 or a little less. If I hook the clutch switch back up the compressor won't come on. Any ideas?