Hi,

Recently I have noticed some strange, sporadic voltage drops/failures in my CL 2009 with keyless and single battery setup. Usually when I press button to turn off the engine, the radio continues to play and the display behind the steering wheel goes out after some time. However sometimes when I turn off the engine, the display behind the steering wheel and the radio immediately turn off, and the watch begin to spin around as if the battery had been temporarily disconnected.
Does anybody have experienced the similar issue? Could this be a problem with some voltage regulator that switches power between the battery and the alternator?

 

electrical issues can be a nuisance on any car - on a merc they tend to be extra special

check by looking at electronic modules under the passenger side carpet (especially for water ingress) re-doing earth points everywhere - and ensuring the battery is 100% - then with a decent power supply to ensure there is enough voltage get on decent diagnostics and see what lies that's pointing you towards