Mercedes B Klasse heating issue

Are you experiencing issues with engine temperature stability? A defective water valve can certainly impact heater performance. Have you inspected the water valve and its wiring harness for any visible corrosion or damage? A blockage within the cooling system could also restrict flow to the heater core. Does the estimated cost include a replacement water valve or solely address the connector?

Engine temp seems normal, no overheating. I haven't had a chance to check the valve itself yet. I'm leaning towards a blockage. The cost they quoted sounded like just for fixing the connection, not replacing the valve. If the valve is blocked, where do I even start looking for the blockage in the cooling system?

Given the stable engine temperature, a complete valve blockage appears less likely. The error code undoubtedly points to the water valve. A faulty connection is a plausible cause. However, I advise a professional diagnosis to confirm functionality before addressing any perceived cooling system blockages. A workshop will be able to test the valve's operation and cooling system integrity.

I took it to a trusted shop and it turned out to be exactly as you suspected: corroded connector at the water valve. They cleaned it up, and the heat is blasting hot again. Appreciate the input!