Had reports from the good lady that the doors have been locking themselves whilst driving (not programmed to do so), and have personally experienced occasions when the tailgate hasn't responded to the release button above the numberplate.

Had a look in the driver's side bellows this morning and think I've found the problem(s); several cracked wires:

 

 

 

So "replace the lock" isn't the only answer. Will have a look at mine since I'm getting locked and unlocked when I shouldn't. Close the door with keys on the car, car running: *lock*. Lock has to go down as soon as the car reaches a certain speed: *lock* and immediately after *unlock*. All in a rather erratic manner. Also the dome light isn't getting triggered by the passenger side door but that indeed has to be one of the microswitches in the lock, but having a look at the wires won't hurt a thing.

Same thing happened to mine only just one wire. The doors were randomly locking/unlocking when driving.

 

Edited 21 October, 20196 yr by TMB

I finally got round to looking at this today, and made some useful discoveries.  It hadn't misbehaved very often, but just enough to be annoying, and I drove it myself yesterday, seeing/hearing unexpected locking.

 

I'd bought some repair wires with the appropriate crimps on, just five though, enough to replace the cracked wires with one or two spares. All set up with soldering iron, heatgun, heatshrink.

 

I decided that access for the work would be much easier if I unplugged all the connectors from the A-pillar sockets, and unthreaded the connectors and cables through the bellows.  Struggled a bit to fit the connectors through the bellows, conscious all the time about fragile wires, but I needn't have worried.

I had played with these connectors on my Polo recently, so I knew how easily the slidey-off bit is removed to allow depinning access. Duly de-pinned one wire at a time from the white connector, which all the cracked wires came out of. Soldered in the repair wires, spreading out the solder joints so they weren't all at one point.  But by now I was getting worried that I wasn't going to fix it with this, because although there were definitely three or four wires with copper showing, there was no damage or corrosion to speak of, not a single strand busted!

BTW, the slidey-off bits of these connectors are quite a bit of the bulk of the connector, so if you are planning to try to extract the connectors through the bellows, take them all off first, and don't put them back on until you've got everything back through the other way when re-assembling:

 

 

 

Decided I needed to check the male pins in the mating half of this and the other connectors but access to even get a phone camera photo is horrible; only just thought about using a mirror now.  Anyhow, I did get the occasional glance of grotty looking surfaces on some of the pins, so decided that that might be the issue after all, rather than the wires.

 

At that point I was almost ready to give up for the day, but just then the missus arrived with a cup of tea for me (well it is her car...) and I described the difficulty I was having in examining, let alone getting anything anywhere near these pins to clean them.  She came straight back with "how hard is it to take off the door?".

Now I didn't know the answer to that, never having tired it, but even before I thought about it, I started to say "but the bit I want to get at isn't in the door" with a slightly impatient tone.  Before I'd finished the sentence I figured out that removing the door would improve access by a country mile, so said "let's see...".

 

It turns out that it's spectacularly easy. Two 13mm nuts, one at each hinge, an M8 XZN screw holding the checkstrap to the door, and of course those wiring connectors if they weren't already disconnected.  I expected it to be moderately heavy so made sure I had a good grip on it before lifting it off the hinges. Absolute piece of cake!

 

 

 

 

Getting that white frame off from round the connector bracket was the next mission, 'cos I could see by now that I was going to want to try to get some of those pins out to clean the crud off them. Bit of a battle, but with that amount of access I knew it was just a matter of patience and pick tools.  Pre-fitting this bit into the bellows (as well as the one at the door end) is about eleventy thousand times easier than trying to get the bellows back onto them in situ by the way, so I knew I wanted to do that.  it only fits the connector housing one way round, so put it into the bellows the appropriate way up.

 

This left just the black housing to extract from the A-pillar. Easy, just a little release tab top and bottom. For once Skoda were actually generous enough with wire length to pull this out far enough to turn it round and see how to release the four separate connectors. Middle two, brown and blue ones are slightly harder than the top and bottom black and white ones, nothing to delay one long though.  Then the same slide-off style clips that let you in to de-pin.  You do need a twin-prong depinning tool for the black one's pins btw. This one has flat power-carrying pins, the rest are all square, and pretty thin and delicate looking, so go gently.  

 

Only really the white connector had any problematic level of corrosion, being at the bottom maybe it gets moister if water gets in past the bellows seal to the pillar?

This was the best photo I took of the grubby pins, couple of them were oxidised on all four sides to some extent. Pretty sure this will have been the problem.

 

 

 

 

Repair pins are available, but none of mine looked too far gone, so just gently scraped clean with a scalpel, after de-pinning each, one by one.

 

That round grommet just below the connectors looked pretty far gone, so I'll probably replace that soonish.

 

I'll let the missus test drive it next time she's out, but I'm confident all will now be well (behaved).

 

 

 

 

Great info. Jen's idea to take the door off was a good-un!

Game changer.

 

Edit: Test driven today without misbehaviour.

Edited 28 May, 20206 yr by Wino

I should have updated this thread a while back, because it wasn't 'problem solved', as it turned out.  Had to revisit the problem a little while later and finally solved it by finding a dodgy solder joint in the passenger side door lock.