SLK 230K supercharger clutch issue

[worried jim]

Is the k40 relay linked to the supercharger clutch?

I ask as the clutch is not engaging so no kompressor boost. I had the dreaded K40 relay fail in September and the car was off the road for 23 days as various garages tried to resolve the fault (the car wouldn't start). Eventually I replaced the K40 unit with a second hand one from Ebay and the car started straight away.

Now I don't do a lot of open highway miles but I've realised that the Supercharger has stopped working and I think it all stems back to the original breakdown, is there anything I can do before I have to throw more money at a garage to look at it?

I appreciate your help. Jim.