Originally Posted by papuc (MMI S4)

After searching the Archives i got some good information on how to fix my sticky A/C buttons. However, there was no tech article on it and since i was bored i thought i would do a quick write up on my experiance.

First things first.


I take no responsibility for any damages, this write up is meant as a guide as your set up may be different, as always the DIY-er assumes all risk and responsibility!

Tools needed:
1. Radio Removal Tool t10057.
(Don't cheap out and buy the ebay ones, I had a bad experiance with those and ended up buying them from the dealer anyways. BTW they only cost $26)
2. Flat head screwdriver.
3. T6 Torx Screwdriver.
4. Towel, Bowl, and hot water.

Ok now that you have all your tools, your ready to get started.

Begin with removing the Radio. This is done using the 4 Radio Removal Tools.

This is how the removal tools are oriented. They pull spring tabs inward to unhook from the radio frame.



Slide the Radio out.





The hardest part is over.

Now onto the A/C unit. Your going to need your Flat head screwdriver for this part. Insert it as shown in the picture below. There is one clip on each side that holds it in. Once you get it lose from the clips it slides out easily.




Unplug the AC unit, you'll want to take it somewhere where you can work on it a little easier.





First thing you have to do is unscrew the front face plate off using your T6 Torx screwdriver. There is a total of 6 of them.

Sorry for the bad picture but the arrows point to where the screws are.



Next your going to have to remove the face plate from all the electrical components. Again your going to need your T6 Torx screwdriver, this time there are only 5 screws.



A closer look:



Once you have removed the 5 screws the face plate should be completely free of any electrical components or wires.



The face place all alone.



Now its time for a HOT bath.



The back side.



After a minute or two I took the face plate out and started to push the buttons that were sticking. They worked as if they were BRAND NEW.



After its relaxing bath, the buttons have to sit and dry.

I used a can of compressed air to help get the water out but I still decided to let it air dry overnight, just in case.




After its completely dry re-install the faceplate to the electrical connection, then screw the faceplate and electrical connections back onto the AC unit. Re-install the AC unit and Radio and your done!

Overall the hardest part was getting the radio out. I almost wanted to just rip it out and replace with with a NAV unit but after some forced persuasion it came out.

There you go, that's it. Haven't had a problem with the buttons since. And yes I know there are easier ways to get this done but this way i felt 100% sure that all the sticky stuff was removed for good!

**not all pictures are mine, so thanks goes to those who were kind enough to share them with AW**