Becker DTM Operating Manual page 64

To remove the unit, it must first be unlocked. To do this, push in both slides to the second detent position as shown in Figure A.
Subsequently, withdraw the unit with both slides (Figure C). Then remove the slides by pressing the springs on the right and left
sides of the unit.If the unit was previously installed in another vehicle, it may be necessary to adjust the springs on the unit before
installation. To adjust the springs, insert slide as shown in Figure D and afterward adjust as shown in Figure E (gently press slide
in the direction of "1" while at the same time moving the slide in the direction of "2").
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