I replace the compressor, dryer, flushed the system, charged with oil and freon, the a/c lights up when the button is pressed and I here a click behind the button but the compressor will not turn on. Removing the connector for the 3 wire low pressure switch will make the compressor cycle, it makes the air cold but the button is to no avail. does any one know where the relay is or have any ideas? 2005 Sprinter 2500