My 2004 S211 cargo cover has developed the dreaded 'machine-gun' noise when closing. When you close the tailgate and the luggage cover gets pulled down, it doesn't stop when it reaches the fully closed position, and the worm gear continues to run.

I've changed the reed switch in the passenger side runner and checked that the magnet is still in place in the end of the cargo cover lug.

When I test for continunity at the reed switch connector, it shows circuit closed (continuity) when the lug is at at the stop position in the runner. Moving the lug slightly up the runner shows open circuit (no continuity) - I take it this means the switch is working correctly?

If so, is there anything else I need to look at? Does it point to a faulty SAM module? I've got an iCarsoft code reader and there's no error codes for the rear SAM.

Any help/thoughts appreciated!