Mercedes-Benz pmn Operator's Manual page 240

Controls in detail
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Folding the backrest forward
The release handle 1 is located in the
trunk.
Pull release handle 1.
Fully retract and fold rearward head
restraints ( page 102).
238
Pull release handle 2.
Fold seat cushion 3 forward.
Fold backrest 4 forward.
Returning the backrest to original
position
Fold backrest 2 rearward until it
engages.
Fold seat cushion 1 rearward until it
locks into position.