Bartfarst

In my experience the same little motors crop up widely across VAG products, principally in door locks etc.

OK, a follow-up to my post earlier today. I went one step further and, in doing so, I reckon I've got to the real root of the issue. Firstly, none of the white grease inside the unit had solidified to the point where it would impede movement of the mechanism. I removed and replaced all the grease I could find, but this was not the issue. Having removed the Mabuchi motor I identified that throughout one rotational cycle of the motor, the electrical resistance across the terminals/connector varied significantly. Accordingly, I suspected either one coil of the armature might be open circuit, or that there was an issue with the commutator/brushes. So, I managed to peel back the two steel tabs holding the motor assembly together and then withdrew the front of the motor, which includes the commutator and armature, from the body containing the permanent magnets. I was then able to measure the resistances across the three armature coils, each of which was in the order of 6 - 7 ohms, balanced, and hence the armature was not at fault. Peering into the narrow gap between the armature and the drive end of the motor I was able to see the brushes which looked complete and obviously had much life left on them. However, the commutator surface was heavily contaminated with carbon residue. Some of this I was able to remove with IPA on the stick of a cotton bud - the end of a standard cotton bud is too fat to get onto the commutator - but I was able to remove the remainder with a fine jeweller's screwdriver. I then reassembled the motor and ran it on the bench as 12V for a couple of minutes just to bed the brushes back in again. I then remeasured the resistance across the motor which came in a consistent 13 ohms irrespective of the rotational position of the armature. I then reassembled the actuator body, supplementing the now broken clips holding the two halves together with a small zip tie. I then bench tested its operation again on 12V to confirm reliable operation. I then reinstalled the unit and put back the large amount of trim etc which had to be removed to access the connection to the main wiring harness. Hopefully this will now be good for another 160,000 miles! So, the main conclusion is that, in my case anyway, degradation/contamination of the motor commutator was the root problem. On reflection, I personally doubt that spraying with WD40 etc would have penetrated sufficiently to have got to the inside of the motor, let alone cleaned all the contamination off the motor commutator. The process I've described is a bloomin' fiddly one, but I think it works. It also saved me three days wait and £51.30 which the local Skoda dealer wanted to charge for a new, OE item. Hope this helps.

I may have a new way of opening a stuck flap lock. I measured the resistance at the connector which was about 500 ohms: too high, but not open circuit. So I set my bench power supply to 30V and gave it a quick pulse and, hey presto, it opened. After multiple operations the resistance fell but to varying lower values. Some variation may be expected due to commutation but this looked excessive. I suspect the ubiquitous Mabuchi motor is on the way out. So a new unit is on order but I'm tempted to add wires so that a higher dc voltage can be applied without dismantling the interior. Hope this helps.

I have the same problem yet I've seen in the handbook that a low performing battery, which I have, can be detected by the Battery Control Module and high current non-essential services (and seat heating is listed as one of them) are suspended. I hope to get a new battery in the next few days so will let you know if that solves the issue.

Ordered thermostat Febi 172376 off eBay: £10.94. Removed airbox, battery and battery tray. It might be possible to do this without removing the battery, but I was changing the DSG filter anyway so I did and it made the whole task much easier. Having crimped both hoses, I was able to remove the far hose from the DSG oil cooler then fold the pipe containing what VAG call the "coolant regulator" backwards and underneath the other pipe to the DSG oil cooler which made it much easier to facilitate exchange. Minimal coolant was lost during the process. The thermostat I removed offered no restriction to being blown through and, when dismantled, the wax stat capsule within was seen to have failed. The new unit offered significant restriction, the only flow being through what I presume to be a small hole which allows bleeding of this line. Now the car warms up just as it should, which was just as well as I doubt I would have ever reached the min 35 deg C DSG oil temperature at which the fill level is determined had I left this problem unaddressed. Thanks to the OP and others for describing this problem.

Thanks for accepting me onto the forum. I have just purchased a Skoda Superb Estate II 2014 170hp TDi and look forward to sharing my experiences with you. Bartfarst