Mercedes GLA cruise control problem

I have a GLA, and I had a similar experience: cruise control failure and an error code pointing to a connection issue. Before paying for repairs, check the brake light switch and the fuse box. A faulty brake light switch can disable cruise control as a safety measure. Also, a blown fuse in the fuse box might be the problem. The cruise control system sometimes shares fuses with other components.

That's interesting about the brake light switch and fuse box. Where is the fuse box located, and which fuse should I check? How can I test the brake light switch? Can I do it myself, or do I need special tools?

The fuse box location should be in your owner's manual; there are often multiple fuse boxes. Testing the brake light switch is trickier without diagnostic equipment. You can visually inspect it for damage, but proper testing requires a multimeter to check for continuity. Honestly, given the complexity, it is best you let a workshop diagnose it. My issue turned out to be a corroded connector, and the repair was straightforward, but diagnosing it took some know-how.

Thanks for the advice. I took it to my mechanic, and you were right. It was a corroded connection. They cleaned it, and the cruise control is working again. Total cost was 95€, so not too bad!