A180D CDI 2015 - auxiliary battery issue / head unit
alternator belt snapped, car was being used by a friend who not only didn't realise, but continued to drive it without it, this hammered the battery's,
the tensioner and belt has subsequently been replaced, I've checked the fuses and the auxiliary battery, all of which is fine, however the comfort elements on the car will not come on , head unit isn't getting power/ and the sos system won't activate, is there a voltage regulator issue? Or what else should I be looking at before spending a mint with Mercedes, been plugged into two different readers both state no voltage to head unit . But aux battery is fine as got a brand new one just in case from MB, charge is going from battery to all other systems except comfort, which i understand deactivated itself prior to battery completely dying?
thanks in advance


