So a fairly common problem along the MQB platform such as golf, octavia, superb and such is the steering wheel control thumb wheels either become intermittent or in my case, they would operate on their own randomly. Heres a guide to fix it:
Cause:
As the thumb wheels rotate anything that is on your hands ends up behind the wheel and gunks up the internal switch sensors and mainly the hall sensor which causes the fault.
Tools required:
Plastic trim removal tools
Flat head screwdrivers
Small picks
Small mirror
Torx screwdrivers T30, T25, T6
Contact cleaner
Small brushes for cleaning such as makeup brushes
10mm spanner
The first part is actually removing the steering wheel controls from the steering wheel. As we are working with airbags here you will have to disconnect the battery - take note if you have a keyless car to turn off the steering lock before disconnecting the battery.
Allow the car to sit for 10 minutes to discharge anything in the airbag system for safety.
Next you will be removing the upper steering wheel trim above the indicator and wiper stalks, this is done by simply pulling up on the trim closest to the steering wheel end. In the photo below indicated with a red arrow. Once this is done just flap it out the way towards the instrument cluster.
We now how to remove the airbag itself. First adjust the steering rake all the way closest to you and down to give room behind the steering wheel. Turn the steering wheel 90 degrees in either direction so a spoke is facing straight up.
I was unable to photograph this as its so awkward to get to, but using a small mirror and flat screwdriver look into the back of the steering wheel you will see a metal clip that needs pushing into the centre of the steering wheel till that side of the airbag pops out.
Rotate the steering wheel 180 degrees the other way and pop this clip out too.
Disconnect the 2 plugs for the airbag and steering wheel control and put the airbag aside.
Now if you have DSG there will be 2 very small white plugs going into the backs of each side of steering controls, simply disconnect these.
The steering controls can now be removed by using gentle force and the trim tools and will come out complete with the black trim as well, be careful not to damage any of the clips as you pull it out, there are no screws but be careful.
Now you have the steering controls off the car the hard part is done.
Turn them over on a soft surface as to not damage them. And remove the 2 small screws on each side to separatex the controls from the actual black trim and making sure to remove with the ribbon cable and not damage the cable. Put the black trim aside.
Now we have the controls on their own and the following must be repeated for both sides!
Undo the 2 tiny screws with a red arrow and also pop the clips open for the 2 blue arrows
Slide the back cover down the ribbon cable and out the way to expose the circuit board so it looks like below
Now lift the circuit board out of the plastic housing to expose the front face of the circuit board, we will start with the circuit board cleaning first, get some of your contact cleaner (if its a spray, spray some into the lid to have a small bowl of liquid to dip your makeup brushes in) and you are going to wipe clean all of the arrowed parts shown (even if they dont look dirty!)
Next the thumb wheel sensor itself needs a clean, be very very gentle here, the components can be damaged if you are rough. You are going to use a clean brush with contact cleaner to clean inside this sensor, both sides on the inside faces where you can see the hole, and the opposite face too.
This is the circuit board clean now. Next is the contact pads and thumb wheel itself. First for the contact pads give them the same treatment as above on the arrowed parts
Then pull this rubber cover off to expose the inside of the back of the control face. Be careful and take note of the small plastic 'plungers' that will fall out and need to go back in the holes arrowed blue below.
The arrowed red section is the sensor pickup for the thumb wheel and where build up mainly occurs. This needs a very thorough clean with contact cleaner and the makeup brush as you rotate the thumb wheel to get every side of it. The small cut outs in this little pickup wheel need to be free from everything, including any lint or build up.
Once this is done, repeat the whole procedure for the other side.
Now you can start rebuilding everything. Place the 2 plungers in the hole and put the rubber cover back over the top the right way up. Rest the circuit board back down on top making sure to locate it correctly. Refit the plastic cover and the 2 screws per side.
Once both sides are done, refit to the plastic trim piece and clip it back onto your steering wheel gently with light pressure to push the locating pins back into place.
Dont forget to reattach the DSG paddle plugs and then refit your airbag plug and steering control plug before refitting the airbag into the steering wheel - push the airbag till you hear the click of both sides of the clips re-engaging.
Refit the trim piece behind the steering wheel now starting closest to the dashboard this time.
Reconnect the battery now and start the car. You will have a dashboard full of errors at this point - dont panic - just slowly turn the steering wheel lock to lock twice then restart the car again, all errors should be gone.
Congrats - you are done, hard work paid off and saved yourself the price of a new set of controls at £250!!!