Mercedes GLK Steering Wheel Controls Issue

Sounds like a possible sensor problem or an issue with the control module itself. Have you inspected the wiring harness that connects to the steering wheel? A faulty cable connection could certainly produce the symptoms you're describing. The control module essentially translates your button presses and relays the correct signals to the car's systems.

That's a good suggestion about the wiring. When you mention the wiring harness, are you referring to the connector that plugs directly into the back of the steering wheel controls, or are there other connections I should be inspecting further along the line?

Yes, I was suggesting checking the connector at the back of the steering wheel initially. However, it would also be beneficial to inspect the wiring extending from the steering wheel down the steering column, as this is a frequent location for wires to become pinched or damaged due to the steering wheel's movement. If that appears to be in order, I'd recommend taking it to a workshop to check the sensor. Locating it yourself can be difficult.

Thanks for the assistance. It turned out to be precisely what you suspected – a broken wire within the steering wheel. A swift repair at the workshop set me back 95€, and everything is functioning correctly once more.