Sticky rotary switches on PCCM unit
- Thread starter Berin
- Start date
I had the same problem it's due to plasticiser leaching to the surface over time, initially the buttons feel good to the touch but over time they become sticky.
I think the replacement knobs are circa £35 each from Porsche so to avoid this cost I got rid of the stickiness using an orange based solvent. However, a word of caution: despite taking the buttons off, cleaning them on my work bench and washing them in soapy water to remove any residue solvent before replacing them, somehow a trace of solvent found its way onto the a/c temp control switch. Apparently the a/c switches are only painted black and a trace of solvent was enough to strip the paint. On close inspection I noticed that the fan speed switch was also showing signs of wear (not solvent related) so I ended up replacing both these controllers with new ones. The internet has lots of images of worn 997 a/c controllers so I would probably have had to do this at some time any way but trying to save a few bob ultimately involved quite a complicated replacement procedure.
I think the replacement knobs are circa £35 each from Porsche so to avoid this cost I got rid of the stickiness using an orange based solvent. However, a word of caution: despite taking the buttons off, cleaning them on my work bench and washing them in soapy water to remove any residue solvent before replacing them, somehow a trace of solvent found its way onto the a/c temp control switch. Apparently the a/c switches are only painted black and a trace of solvent was enough to strip the paint. On close inspection I noticed that the fan speed switch was also showing signs of wear (not solvent related) so I ended up replacing both these controllers with new ones. The internet has lots of images of worn 997 a/c controllers so I would probably have had to do this at some time any way but trying to save a few bob ultimately involved quite a complicated replacement procedure.
Greenman986S
PCGB Member
There was a DiY piece in a recent edition of 911&Porsche World
Not difficult to do at home
Not difficult to do at home
Yep, did mine with the hand sanitiser left over from Covid days! Takes a few goes but got rid of the stickiness.Isopropyl alcohol or alcohol-based hand sanitizer/hand wipes could do the trick?
Jeff
I cleaned mine with a microfiber and nail polish remover. Worked fine.
Well, I went and bought new ones, after finding none of the cleaning methods lasted very long. But steel yourselves - £105 for the pair 
.
Some tips on replacing them, it is quite easy but DO NOT try to prize the old knobs off.
The knobs are in 3 parts - the outer ring, the centre, and a metal retaining ring.
To remove the old knobs, get a fingernail or a tiny jewellers flat blade between the outer ring and the centre piece and gently pry it out - it takes no pressure at all.
Under the centre piece is a small metal screw, it's a tiny Torx T6. Don't bugger it up or lose it, you'll need it. Unscrew and keep safe, then lift the out ring off.
Get the new parts, locate the outer ring on the square fitting. Refit the T6 screw very gently, then fit the metal retaining ring, using the lugs, and clip it in. Then press the centre piece in, again locating the lugs correctly.
Job done, I can now safely use the PCM again without getting sticky.
.Some tips on replacing them, it is quite easy but DO NOT try to prize the old knobs off.
The knobs are in 3 parts - the outer ring, the centre, and a metal retaining ring.
To remove the old knobs, get a fingernail or a tiny jewellers flat blade between the outer ring and the centre piece and gently pry it out - it takes no pressure at all.
Under the centre piece is a small metal screw, it's a tiny Torx T6. Don't bugger it up or lose it, you'll need it. Unscrew and keep safe, then lift the out ring off.
Get the new parts, locate the outer ring on the square fitting. Refit the T6 screw very gently, then fit the metal retaining ring, using the lugs, and clip it in. Then press the centre piece in, again locating the lugs correctly.
Job done, I can now safely use the PCM again without getting sticky.
What happened to Climarepair.com they used to sell all the switches for the PCM at reasonable prices
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