Galant's AC Woes: Solar Sensor or Something More?

Hey there! I have some experience working on cars, mainly DIY maintenance and repairs. I had a similar issue with my 2003 Mitsubishi Lancer Diesel about a year ago. The climate control system was acting up just like yours. After taking it to my trusted mechanic at AutoFix Workshop, they found a defective wiring harness that was causing the AC control unit to malfunction. The repair cost me around 155 Euro, but it fixed the problem completely. Could you share more details about your car, like: Any error codes showing up? Does the AC compressor kick in when you turn on the system? Have you noticed any other electrical issues? This would help me give you more specific advice based on my experience with the Lancer. The Galant and Lancer share some similar components, so it might be the same issue.

Thanks for the reply! My Galant's at 108978 KM and had its last service about 3 months ago. No error codes showing up, but now that you mention it, I can't really hear the compressor engaging when I turn on the AC. I've checked all the fuses, and they seem fine. The weird thing is that sometimes it works perfectly fine in the morning but gets worse throughout the day. Haven't noticed any other electrical issues though. I might check out AutoFix Workshop, are they still good with older Mitsubishis?

Hey again! Yep, I can totally relate to that morning/daytime performance difference you're experiencing. My Lancer did the exact same thing, worked fine in the morning but got worse as the day went on. That's actually what made me initially suspect the solar sensor too, but it turned out to be that wiring harness issue I mentioned. And yes, AutoFix Workshop is still great with older Mitsubishis! They've actually worked on quite a few vintage models lately. The fact that your compressor isn't engaging consistently is really similar to what I experienced. In my case, the faulty wiring harness was causing intermittent connections to the compressor clutch, super annoying! Since your mileage is pretty close to what mine was when I had the issue (mine was around 115000 KM), it might be worth getting that wiring checked out. One quick test you can try: next time it's acting up, try gently wiggling the wiring near the compressor (when it's safe to do so, of course!) and see if that makes any difference. That's what helped diagnose my problem. Just make sure to mention these symptoms to the guys at AutoFix, especially the morning/daytime difference. They'll know exactly what to look for since they've seen it before on my Lancer. Hope this helps!

Thanks so much for all this detailed info! That's really helpful about the wiring harness, I never would've thought to check that. I'm definitely going to try that wiggling test you suggested, sounds like a smart way to diagnose the issue. And it's super reassuring to hear AutoFix Workshop is still good with older Mitsubishis. I'll give them a call tomorrow and mention the symptoms you described, especially about the morning/daytime difference. Fingers crossed it's the same issue as your Lancer, at least I know what I'm looking at cost-wise then. Really appreciate you taking the time to share your experience with me!