M Klasse Windshield Washer Heater Issues

I had a similar problem with my M Klasse a while back, though not specifically during winter driving. Did you check the fuse box? It might be a simple blown fuse related to the windshield heater circuit or even the washer motor itself. Easy place to start before diving deeper.

Yeah, I checked the fuses. All seem fine. The error memory says 'windshield washer heater malfunction' and now the spray nozzles are frozen solid because of the cold. Any idea which cable or plug connection is likely to be defective?

Sounds like it goes deeper than a fuse then. I never got that specific with mine since the dealer took care of it. If you're seeing that error and experiencing frozen nozzles, especially after checking the basics, I'd suggest getting it looked at by a workshop. Could save you some time and headache trying to trace wiring in this weather.

Alright, thanks. Took it to a shop, and you were right, it was beyond a simple fix. They found a defective plug connection on the heater. Cost me 95€ to sort out.