Breezy_Pete

Genuine coolant sensor looks to be only around £30, but I'd be highly suspicious that the real issue is contamination of the coolant. Are you having to top up the coolant from time to time?

Sorry, no. No experience of these connectors at all. Some photos from various angles may help someone think of suggestions.

Shouldn't be tricky TBH. 🙂

This inventive fella worked out that if you drill a small hole in just the right place you can release the deadlocked lock with a Tx20 tool inserted through said hole and turned a little in the appropriate direction. Quite tempted to make a suitable template or two for the Fabia and drill some 'get out of jail' holes ahead of need. 9N3 doorlocks | UK Volkswagen Forum

Check again for presence of sensor in sump.

I think that's just normal behaviour. My Polo does the same. Brief warning light that goes out whether or not you plug in your seat belt, no audible warning.

It's not a relay it's just packaged like one. It's a CAN converter. Bit more to it inside than a relay, I'd guess.

Nope, not Torx at all. 12-points not 6, therefore XZN or spline. Can find the appropriate tool size if it's XZN by measuring or just by buying a set. triplesquaretable.pdf

@Dimitris Gavriilidis Who did the service, and is it possible that they accidentally, or deliberately set it to be on a variable service schedule instead of fixed interval as it probably was previously if there is no sensor?

Since the very first Fabia, coolant temperature has been conveyed to the instrument cluster from the engine ECU via CAN data. It seems to me very likely therefore that the fault is local to the cluster, as any CAN problem would surely affect many other functions. If your cluster can display oil temperature, it's probably best to just use that going forward, rather than try to fix the water temp gauge.

It doesn't sound to me like it's worth getting it booked in or checked out.

No, he was just mis-remembering seeing the battery light go out before engine fires up. He's saying they both do the same as what we are saying they should do.

The best way to find the correct part number will be to read it off your existing switch.

But may help to explain the slightly sub-optimal starting behaviours observed.

Take the car for a decent drive or connect a charger for a few hours if you feel the battery needs topping up.

The battery light should go out once the engine is running. Not before.

I think the light should only extinguish once the engine has started.

Great news. So maybe the original N280 was the only real problem? A previous owner possibly changed the HVAC module whilst trying to fix the system's problems that were (unknown to them) caused by failing N280, without success?

There may be a restrictor/jet within one of the fittings, to make one narrower diameter. if there are no leaks in the system (EGR valve diaphragm?) then there should not really be any significant volume of air being moved, the diaphragm should make it a closed system, so high impedance to airflow may be no problem.

I think I would expect to connect to the uncapped one. They may well be equivalent, hard to see in that photo. I guess one might be routed to each side of the valve? Most likely both will be connected to the vacuum pump side, leaving only the servo on the protected side of the one-way valve.

Not sure if 'fingers crossed' translates in to Dutch, but I'm sure you understand the meaning. It sounds consistent with the fault code, if it was making intermittent contact.

Are you certain that it wasn't brake fluid? That would have a much easier way of entering. Maybe the real fault is master brake cylinder leakage?

If the pump exhausted air that way by design, I think a lot of oil would leak out of there too.

Remind me, is your steering wheel on the left or the right? If it's on the left, your servo vac hose should be part number 6Q1 612 041DF, if it's on the right it should be 6Q2612041BS, I think. Your engine has the PR-code T9V, I think. https://skoda.7zap.com/en/cz/fabia/fab/2002-225/6/611-611070/

It pulls air out of the brake servo, and any other connected vacuum 'motors', exhausting any air that it pumps into the cam cover via this non-return flap valve. I would not expect that hose to be loose, it should not allow any air in except what comes through that pipe that you are moving.