I am going with what I know about general a/c (not specific to e53) but...



well if the wire(s) to the clutch is disconnected the clutch will not engage and the light will still many be on. Did you do all you can to see everything is still connected?? If the outside temperature is below 60 deg f the clutch may not engage and the light will still be on. You are in the east cost is it like 50 deg outside when you tried.



IF you have zero freon the clutch may not engage. Were you able to confirm that you have some pressure in your a/c system??? The freon is added through a valve like your tire (except bigger). If you don't have any guages you can see if you have at least some freon by removing the dust cap and press the valve stem to see if some freon is coming out (like you tire). Or you can get one of those cheap 134a charging kit that have a guage on it and it will have instructions on now to check and charge you a/c system. But I don't think low pressure is you problem. The clutch should still engage in low freon.