volts battery service

Hi currently, have W204, the car appears to be blowing front sam unit. No heated seats, auto lights, wipers or horn not working. Replaced front sam, worked for a week. And it stopped working again. Could this be a fuse or relay? The main thing I would like working is the wipers. If I...

Probably a stupid question but - in the servicing menu of my A150 there is a display item of 12.2 V (looks more like a U than a V) anyway is that supposed to be the actual battery voltage or is it something else used in servicing or diagnostics? Thanks for looking.