Mercedes G Klasse Heating Problem

Water valve issues on a G Klasse are not fun. Start by visually inspecting the water valve and its connections, looking for corrosion or damage. Also, check the coolant level, as a low level impacts heating performance. It might be simple, but these things can be tricky. Did you check the fuse?

Good call on the fuse, I did not consider that. Coolant level is okay, right at the mark. When you say inspect the connections, do you mean the electrical connector, or the hoses too? I see no coolant leak, but I wonder if the heater core is partially clogged. Is there an easy way to check that without taking the dash apart?

Check the electrical connector first. Wiggle it and see if anything changes. Check the hoses too, looking for cracks. It is hard to say about the heater core without testing. It sounds like you have done a decent job troubleshooting. Maybe get a second opinion from a workshop before replacing things? It could save money if you misdiagnose it. Hopefully it is not a coolant leak!

I appreciate the advice. I wiggled the connector and cleaned it, but it did not work. I took it to my mechanic. The water valve was faulty, like the error code said. 97€ later, the heating is back to normal. Thanks again for pointing me in the right direction!