It happened on my 190D on occasions but not on all 4 doors. The problem is the latch got stuck and does not release. It has been sitting for a long time. The door will open from the inside, if you can get inside through 1 door.

You can try using a rubber mallet and bang on the part on top of the car handle where the latches are. Making sure the knobs are all in the up position and bang the door gently. It may work. Or if you can put a long wire through a window slot ( if possible) and pull the inside release of the opposite door. Good luck.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.