92 500SL storage compartments
 

Can someone tell me how to unlock the storage compartments in the doors and behind the seats? My jumper cables and owner's manual are in the rear storage compartments but I can't get them to unlock.

Try locking/unlocking the car a few times. On a 129, the door pockets, glove box, eyeglass compartment, center console, and rear compartments are all part of the central locking system. It's possible that one of the actuators is stuck. This feature allows some measure of security if the car is left unattended with the top open.