I know it is a slim chance but there might be an easy answer to this – or at least some good ‘first places to look’ but I gotta start somewhere.

Car is 1986 300E W124 M103 with 224k miles.

I have begun to have phantom lock and unlock of the doors. Sometimes I have to lock all three (door, door and trunk) locks several times to get the car to lock. All the locks work but it unlocks right after I lock it. Sometimes I return to the car and find it unlocked. Sometimes it locks all by itself while driving down the road. Sometimes only the door I open with the key opens, the rest stay locked, sometimes for hours of driving, then they all unlock when I go to lock the car. (The doors all lock normally but immediately unlock)

Additional symptoms:
Fan cuts out intermittently (sometimes maybe under throttle). Sometimes I can make it go on by operating the window buttons. If I hold the window button in ‘up’ the fan goes on – off when I release, sometimes I have to hold two window buttons down to get this effect. Sometimes but not always the radio cuts out too – but the presets are not erased. Sometimes the wiper operates at ‘double time’ – intermittent and normal are at fast speed and position III is super fast – like 4x instead of 2x – but only when the car is in intermittent no fan mode.

Thanks for any help, David

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David
1986 300E Anthracite + ECodes + MB Mileage Award

You need to inspect the TRUNK lock. It can spring unlocked and unlock the whole car.

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2012 E350
2006 Callaway SC560