If you have the "right" mirror selected, and it still won't dip in reverse, check to see if your back up lights are illuminated.

The switch in the shifter module does both functions.

Remove your shifter wood and look for two connectors in the rearmost side of the shifter housing. One connector has about a half dozen wires and the other has two. You want the two wire connector.

Unplug it and use a paper clip or jumper to short the two pins in the connector. This should make the mirror dip and the reverse lights come on. As long as your key is in II position.

The fix is to either replace the range recognition switch in the shifter or open it up and clean/tweak the contacts.

The position of the mirror when it dips can be programmed, the procedure is in the owners manual.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech