Can any one advise, my electric side step retracts OK but alarm sound sounds when engine starts, I've played around with the micro switch underneath, seems to work OK, searched high and low for the actual alarm so I can disconnect it but can't find it anywhere, it's an annoying high pitch buzz which fades slightly then increases etc. I own a hymer Mercedes S650 2005 model, nothing in manual as to location, have looked under drivers seat etc, (LHD), slowly loosing the will to carry on lol, any help would be appreciated.
Terry,, based in Bulgaria with open roads and lots to discover.

Usual problem can be solved with a coin or two on the top step to give the microswitch a bit more push. Gaffertape to secure the coin/s. Replace every two years !
Bill

Will try tomorrow, somehow I think it won't work, taking the beast for mot first regardless of the annoying buzz, thanks Bill in advance, fingers crossed

Tried Bill's idea but sadly warning buzz never changed, got the Mot successfully although reverse lights never worked. Lots of electric faults at the moment fridge won't work on hook up, wing mirrors not working electrically, electric skylight not operating, nightmare lol, but I won't give up yet.

I'm surprised a functioning reversing light isn't a requirement of MOT.

Reversing seems not a priority in Bulgaria, I guess in a years time if not sorted they might say something 🤔

Fridge now working, that's a bonus as it's 34+ hot here, the step warning buzz is annoying, to get to the micro switch it looks that I will have remove the whole step assembly just to get the electrical cover off,,,,, grrrr

Earplugs!!

Earthing can be a problem with the micro switch on steps.

I have wired brushed the earth, thanks for that but no joy, when time I will remove the whole lot, along with the earth & reassemble.