How to Replace a W124 Window Regulator

1. Open up the door that has the broken window regulator. Sit inside the vehicle for added comfort while carrying out the work. Use a Phillips-head screwdriver to remove the mounting screws that hold the door panel onto the door. Place the screws in a safe area. Lift the door panel away from the door.
2. Take the screws away from the door handle and pull the handle away from the door. Use a wrench to remove the mounting bolts fixed to the backing plate. Lift the backing plate away from the door to gain access to the window regulator.
3. Unhook the electrical wiring that connects the regulator motor to the regulator. Pull it from the regulator connector with your hand.
4. Use a hex wrench to remove the bolts that connect the regulator to the window. Remove the remaining bolts from the bottom of the regulator and lift it away from the door.
5. Install a new regulator by fixing the bottom mounting bolts to the regulator first before attaching the hex bolts that connect it to the windowpane. Reconnect the connector from the motor to the regulator by pushing the cable into its connector. Reattach the rest of the door assembly by following the removal steps in reverse.