S2000 Cabin Heat & Mirror Defrost Issues, Help Needed!

Hey there! I have some experience working on cars and had a similar issue with my 2004 Honda NSX. Those heating problems can be super annoying! Had exactly the same symptoms, no cabin heat and frozen mirrors. Turned out the cable connection to the water valve was shot, and water wasn't flowing properly through the heating circuit. My trusted mechanic diagnosed it pretty quickly and replaced both the faulty connection and the valve plug. Cost me about 155€ all in, and it's been working perfectly since then. Quick question though, have you noticed any coolant leaks or had to top up your coolant recently? Also, does your temperature gauge show normal readings? These details would help me better understand if you're dealing with the same issue I had. I've actually owned a few Hondas (including a Civic), so I'm somewhat familiar with their heating systems. Let me know more about your situation, and I'll try to help further!

Thanks for sharing your experience! Currently at 260214 KM after my latest service. No coolant leaks that I can see, and the temperature gauge is reading normal. Really helpful to know about the cable connection issue you had, that's giving me hope it might be something similarly straightforward. I'll definitely get my mechanic to check the water valve and connections. Did you notice any particular symptoms before the heat completely stopped working? Just trying to figure out if I'm dealing with the same problem you had with your NSX.

Hey again! Glad I could help with the initial info about my NSX experience. Yeah, thinking back, I did notice some warning signs before the heat completely gave up. For about two weeks before the total failure, the heat would work inconsistently, sometimes it would blow warm for a few minutes then go cold, especially at idle. The mirrors would only partially defrost too, which was super annoying on cold mornings. Since you're mentioning your mileage is at 260214 KM, it's about the same range where my issues started (I was around 250000 KM). Given that you're getting normal temp readings like I did, and no coolant leaks, I'm even more convinced it's similar to what I experienced. Just a heads up, when my mechanic did the repair, he mentioned it was smart to catch it early. Apparently, if left too long, the faulty valve can sometimes cause issues with the heater core, which would've been way more expensive to fix. Keep us posted on what your mechanic finds! Always curious to hear if my experience helps others with similar Honda issues.

Thanks so much for the detailed follow-up! You've actually made me feel a lot better about this whole situation. Those warning signs you mentioned, the inconsistent heat and partial mirror defrosting, that's exactly what I've been experiencing! Can't believe I didn't connect those dots earlier. It's really reassuring to know you had such a straightforward fix, especially since our cars had similar mileage when the problem showed up. I've already called my mechanic and scheduled an appointment for tomorrow morning. Definitely don't want to risk any damage to the heater core, that's exactly the kind of expensive repair I'd like to avoid! I've made sure to mention the water valve and cable connection issues you experienced, so hopefully, they can check those first. Really appreciate you taking the time to share all this info. It's such a relief to have a better idea of what I might be dealing with. Thanks again for all your help!