GLK Auxiliary Heater Problem

I have a GLK and experienced similar auxiliary heater issues. A defective glow plug is a plausible cause. Have you checked the climate control module for any error codes related to the heating system or ventilation system? It might provide more specific information.

Thanks for the quick reply! When you had the issue, did the climate control still blow regular heat from the heater core when the engine was running, or was the whole heating system not working? Trying to figure out if I can live with it for a bit.

Yes, in my case, the main heating system and heater core functioned normally when the engine was running. The auxiliary heater issue only affected the parking heater functionality. However, I recommend addressing the error promptly to prevent potential complications with the overall heating system. A visit to a qualified workshop for diagnosis is advisable.

Appreciate the confirmation! Sounds like it's worth getting sorted sooner rather than later. I took it to the workshop, and it was indeed the glow plug. 440€ later, the auxiliary heater is back in action. Thanks for the advice!