GLS Lighting System Issue

I've got an electrical problem in my 2017 Mercedes GLS with a gasoline engine. It's clocked 279517 km. The dashboard lights are acting funky, and sometimes the headlights switch on by themselves. I pulled the codes, and there's an error stored related to the lighting system. I'm guessing it's something with the headlight switch or maybe a dodgy fuse box connection. Has anyone else run into this?

4 comment(s)

Sounds familiar. I had a similar issue in my GLS, though the mileage was lower. Have you checked the cable and plug connection of the automotive switch itself? Those things can get loose or corroded over time. Before you start tearing into the fuse box, make sure the headlight switch is properly seated and the harness isn't damaged. These newer systems are sensitive, and even a slight voltage drop can throw codes.

When you say 'automotive switch', are you talking about the headlight switch on the steering column, or is there another switch I should be looking for? And how much of a pain is it to get to the connector? I'm not exactly a seasoned mechanic.

Yep, I'm referring to the headlight switch on the steering column. The connectors can be a bit of a pain to access, you need to remove some of the trim pieces around the steering wheel. Honestly, if you're not comfortable with that kind of work, it might be worth swallowing your pride and taking it to a workshop. A bad move with those connectors could cause more problems than you started with. Estimated repair cost around 95€.

Thanks for the heads-up. I was hoping it would be a simple fix, but I'm probably better off letting a pro handle it. Just got the car back, you were spot on! They said it was a defective cable or plug connection, exactly like you mentioned. Cost me 95€, but at least the lights are behaving now.

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