I have the “Auxiliary Battery Malfunction” message on my dashboard. Went to the official service center and he said I’ll need to replace the voltage divider, but gave me a crazy quote of $500 including labor. Part alone costs $325. He discounted it to $420 but it’s still way too much.

The part number he gave me is MA 205 905 34 14. I found it on mboemparts.com for $105, but my concern is it says “remanufactured”. Same for shopmbonline.com. Does this mean that it’s been used and repaired?

Yes it does, just fitted one this past weekend. Sourced mine from parts.com in the US and a relative sent it to me here in Australia. Works fine, I dismantled mine and the electrolytic capacitors were leaking and damaged other components within the unit so I guess mine cannot be repaired. In my opinion although this is not a new part it is a very cost effective repair for the average person at home