w211 Aux battery change

[merc85]

I did this on my last 211, But cant remember if you have to re calibrate the windows etc or does the main battery keep the circuit going?

 

[Major774]

Just check your windows... If the auto up and down feature is not working then perform the usual steps and they will be working again.

 

[mersum1es]

I theory you can change aux battery if car is in sleep mode, but WIS says disconnect main battery first, change aux and connect main back. I did according that (changed both batteries though), no problems... like above windows/sun roof need to be learned.