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Mercedes-Benz Power Window And Lock Failure


Have you ever tried to opening your power window at a fast food drive thru or a drive-up ATM and you just couldn’t?

If so, you’re likely to be a victim of a power window failure.

A power window system allows the rolling up and down of windows in any modern car.

As such, a malfunctioning power window switch causes communication breakdown between the window button and the motor.

This prevents the up and down movement of the Mercedes-Benz’s windows.

How Mercedes-Benz Power Windows Operate

Power windows allow power to move from the engine to the master control switch operated by the driver through wiring cables.

The master switch takes power directly to the driver’s door and window motor, and indirectly to the passenger window motor through the passenger window control switches.

A fuse attached to the cable wiring prevents a power surge from damaging the master control switch.

Through the switches, both the driver and the passengers can operate the windows.

Common Power Window and Lock Failure Symptoms

Reasons for Malfunctions in Mercedes-Benz Power Window and Lock

A Blown Fuse

Whenever a fuse is blown, one door may fail while others remain operational. The malfunction can easily be fixed by replacing the fuse with a new one.

A Damaged Solenoid

Similar to a fuse, a damaged Solenoid may hinder the lock from operating efficiently and the problem could be the lock solenoid. Replacing the damaged solenoid may require removal of the entire Mercedes-Benz door panel.

A Faulty Key Fob

A faulty key fob may cause lock failure in a power window and door. Diagnosis to locate the possible fault would typically require hooking the fob to a computer to check if the programming is right. A faulty fob that doesn’t send any signal to the computer will likely have to be replaced.

A Dead Key Fob Battery

A dead key fob battery is one of the most common reasons for Benz lock failure. Dead batteries may require replacement if the lock malfunctions.

Broken Wire Connections

Broken wires may cut off the power supply to the car window locks. Holding the window and lock switch either up or down and attempting to open or close the door repeatedly will reveal whether or not it works. If the power window and door locks work intermittently, the most probable cause could be a broken wire connection.

Overheated Power Window Motors

Overheated power window motors inside the power door may cause intermittent power lock failure. When the motor cools down, the power lock may begin to function again.

Malfunctioning Master Switches

The master switch supplies power to the motor in order to lower or raise the power window. A malfunctioning master switch can often lead to a failure of the power window and lock.

Bottom Line

The Mercedes-Benz power windows system is a closed system and may not be inspected during regular maintenance and servicing.

Power window problems are rare, but can occur without warning.

Although fixing a power window problem can be a Do-It-Yourself task, professional mechanics advise vehicle owners to employ the services of a qualified Mercedes-Benz technician capable of diagnosing the exact cause of the failure.

Immediate inspection is recommended as soon as a power window switch behaves abnormally.

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