HHR Heater Issues: Water Valve Causing Poor Heat Output?

Had a similar issue with my 2013 Chevy Cruze last winter, definitely can relate to your heating troubles. Got really familiar with this problem after spending a few hours at my local shop. The car heating system was barely pushing out warm air, which was pretty frustrating during cold days. The initial diagnostic showed it was indeed a faulty automotive valve, specifically the heater control valve that regulates engine coolant flow. Cost me 95 Euro to fix, turned out to be a damaged wire connection to the valve. Once they replaced the connection, the heating worked perfectly again and the error code cleared up. Since you've got engine coolant flow issues, could you share: Any specific error code numbers? Does the temperature gauge work normally? Do you notice any sweet smell inside the car? Got some experience with Chevy heating systems after dealing with this, so happy to share more specific details once you provide this info. Want to make sure you check these basic points since they might save you some trouble and money before jumping to bigger repairs.

Thanks for sharing those details. Just had my 18598 KM service done last month, so these symptoms are pretty recent. The error code is P0128, and yes, the temperature gauge works fine, no fluctuations. Haven't noticed any sweet smell, which is good since that would point to a heater core issue or coolant leak somewhere in the system. Interesting you mention the wire connection to the automotive valve. When the car's running, I can hear a slight clicking noise from behind the dash when adjusting the temperature controls. Definitely sounds like it could be similar to your valve issue. That's way better than having to replace the entire heater core. Would you remember if they had to remove much of the dash to access that connection, or was it a fairly straightforward fix?

Thanks for those details. Yeah, mine made that exact same clicking sound too, definitely brings back memories. When they fixed my Cruze, accessing the valve connection was actually pretty straightforward. They didn't need to tear apart the whole dash, which was a relief. The P0128 code is exactly what I had, it's typically related to the engine cooling system not reaching proper operating temperature. In my case, the faulty wire connection meant the water valve wasn't opening and closing correctly, so the coolant flow wasn't being regulated properly. Pretty much identical to what you're describing. Since your symptoms match mine so closely (same clicking noise, same error code, similar heating issues), I'd bet you're dealing with the same problem. The fact that your temperature gauge is working normally and there's no sweet smell is also good news, rules out a lot of worse problems like engine overheating or major coolant leaks. Quick tip from my experience, have them check the connector pins for corrosion while they're in there. Mine had some buildup that they cleaned out during the repair, which probably helped prevent the issue from coming back.

Thanks for the detailed explanation! That's really helpful, especially knowing it was the same P0128 code and clicking sound. Seems like too many similarities to be coincidence. Going to schedule a repair appointment and have them specifically check the valve connector and wiring first, since it seems like the most likely culprit. Good to know they shouldn't need to tear apart the whole dash to get to it. Will definitely mention checking those connector pins for corrosion too, smart thinking on that. Nice to hear it wasn't a major engine coolant system issue in your case. The fact that you got it sorted without any extensive repairs gives me hope this will be a relatively simple fix. Will update once I get it checked out in case anyone else runs into similar heating problems with their HHR.