I have noticed that my a/c clutch has been making a bad noise intermittently. It makes a clicking/grinding noise. It only does it sometimes and i mostly notice it when i am slowing down to a stop which leads me to believe it may be an issue with the low/high pressure switch. Anyone here have any ideas what could be the culprit?

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2006 E320CDI- current dd
1999 E300TD - retired
Wilmington, NC USA