AC compressor on my BMW X5 won't come on. there is a charge. there is a new pressure switch, but I get a code 15 for a pressure switch, bought another pressure switch recharged it and compressor still won't kick on. if I put Power straight to the compressor it turns on but isn't Cooling. you got any ideas to help me figure this out? Thanks in advance . Its getting hot in tennessee. Need to fix asap.