MCC/Smart Power window switch replacement

What Happens When Your MCC/Smart Power Window Switch Fails?

If you’ve been around long enough to know what it means to work a hand-crank window winder, you will appreciate how fabulous power windows are . . . at least until they stop working. When that happens, there is no way of getting that window up or down without pulling the door apart or damaging the window actuator.

When it fails you won't be able to park securely, or avoid a wet interior if it's raining and the MCC/Smart's window is stuck in the down position.

There are a number of reasons power windows won’t work. It could be due to a blown fuse, broken cable, damaged track, defective actuator or a faulty window switch. It’s best to get a professional to diagnose the fault.

If you are advised that your MCC/Smart has a broken power window switch that needs to be replaced typically, it is the driver’s master switch that fails, as it is used most often.

The master switch is usually a larger component with toggles/buttons to activate all the vehicle’s windows. They are usually found in the door armrest or in the centre console and often a moulded plastic assembly.

Power window switches have toggles/buttons that are flicked or pushed to activate the power window function. They're an electrical device that's connected to the MCC/Smart's wiring either directly or via a control module.

There are a couple of variations to how the circuit operates. One system, when activated, will transfer power to the window motor which will then turn one way or the other depending on whether the window is to open or close.

Other systems close a relay when the switch is activated on the door module. This sends a message to the control module to activate the window motor. This type of system is more likely on a vehicle that has multiple operations on the one module/switch. A window master switch can also have other functions such as mirror and door lock controls included.

When the power window switch fails you may notice:

• The master switch works but the switch for a particular door doesn't work
• Windows don’t operate
• One window doesn’t work
• Intermittent or erratic operation

It's important to be gentle when removing and fitting switches on MCC/Smart's as they are usually made from plastic and can easily crack or split with too much force.

When the power window switch fails it’s more an inconvenience than anything but if your window is open and you can’t lock your vehicle securely and it is subsequently stolen, insurance companies may choose not to pay out on a claim.

And, if the driver's window is stuck in a closed position, just remember not to go through any drive-thru fast food joints!

It’s worth booking a window switch expert through AutoGuru to prevent this inconvenience.