BMW Z4 AC Nightmare: Rear Vent Flap Fix Solutions

Hey there! I had a similar issue with my 2004 BMW Z3 last summer. I've got some experience working on cars, but nothing too advanced. The symptoms sounded exactly like what I dealt with. In my case, it turned out to be a faulty wiring connection to the climate control module. My trusted mechanic found that some cables had become loose and corroded over time. The fix involved replacing the connection and testing the system, cost me around 95 Euro and took about an hour. Before I can give you more specific advice, could you share: Which error codes are you getting? Does your AC fan work at all? Have you noticed any unusual noises when changing temperature settings? Also, I know the Z4 and Z3 have some differences in their AC systems, but many of the common issues are similar. Let me know these details and I might be able to help further!

Thanks for the detailed response! My Z4 is at 94465 KM and just had its service last month. The fan does work, but I'm getting a weird clicking sound when switching between temperature settings. The error code I'm getting is P0532. The AC compressor seems to engage but there's no cold air coming through. I checked a few fuses already, but haven't found anything obvious. My mechanic is booked solid for the next two weeks, so I'm trying to gather as much info as possible before taking it in. Starting to think it might be more than just the ventilation flap I initially suspected. Did your mechanic mention anything about checking the compressor or refrigerant levels during your repair? I'm hoping it's just a wiring issue like yours and not something more serious.

Oh that clicking sound you described, I had exactly the same thing with my Z3! When you mentioned the P0532 code, that actually rings a bell. After my initial wiring fix, I had a similar issue pop up again a few months later, and it turned out to be a bit more complex than just the loose connections I mentioned before. In my case, that clicking sound was actually the compressor trying to engage but failing because of low refrigerant pressure, which explains your P0532 code (low-pressure side circuit). My mechanic did end up checking the refrigerant levels, and sure enough, we had a slow leak in one of the lines. The fix for me involved: 1. Finding and repairing the leak (it was at a connection point) 2. Recharging the AC system 3. Double-checking all the electrical connections Total cost ended up being around 250 Euro, but it was worth every penny. The clicking stopped completely, and the AC has been ice-cold ever since. Given what you're describing, I'd bet you're dealing with something similar rather than a ventilation flap issue. The symptoms are just too similar to what I experienced. If you're handy with cars, you might be able to check the refrigerant pressure yourself with a gauge set, but honestly, with these systems, I'd recommend waiting for a professional to take a look.

This is super helpful, really appreciate you sharing your experience in such detail! That clicking sound being related to the compressor and refrigerant pressure makes a lot of sense. I was going down the wrong path thinking it was just the ventilation flap. I'll probably hold off on doing anything myself and just wait for my mechanic appointment. At least now I can go in with a better idea of what might be wrong. The 250 euro repair cost doesn't sound too bad considering the alternative of replacing major components. Fingers crossed it's just a leak like yours was! I'm actually relieved to hear this is a known issue that has a straightforward fix. Would have hated to find out I needed a whole new AC system. Thanks again for walking me through your experience, it's given me a much clearer picture of what I might be dealing with!