Breezy_Pete

Does the car have DRLs? The wire goes direct from that 2-way connector pair at the gearbox to pin 9 of connector XS4 at that module above the accelerator pedal. But there's a connection also to the "Day driving lights relay" that I've not come across on mk1s. Potentially if that relay is poorly it could be pulling down that voltage, as could any partial short like rainwater affecting cracked insulation somewhere in the engine bay for example.

I'll have a look at the circuit diagrams later; but I'm almost certain that the blue wire originates from the Central Electrics module above the accelerator pedal.

If it were useful to do so (not in this case) you could measure while the connector is plugged in by stabbing a needle through the wire insulation and connect your meter probe to the needle. Your blue wire voltage definitely looks too low.. I'd expect about half a volt less than ignition 12V. What year is this Fabia? And what is the resting voltage across the battery terminals at the momnet?

What was happening at time of voltage measurement, where was the measurement done? i.e. did you measure at alternator connector? With it plugged in or unplugged? Engine running or just ignition on? I can't imagine the HVAC module is in any way related.

If you have to do a DIY messurement, you could use the alternator fuse as a shunt. Might be slightly non-linear but that could be calibrated out. For any sort of accuracy you'd probably also need to measure and calibrate for local area temperature also.

Must be in a VCDS measuring block within whichever module is responsible? For the VW? Ross-tech forums may be worth searching. Alternatively a guy on here called @fabdavrav is clued up on this stuff, I believe.

It's the blue wire to the alternator you want to check, not the load signal one. Not sure how the wiring's done on a mk2, have a look.

Item 6A here https://skoda.7zap.com/en/cz/fabia/fab/2009-608/3/300-300010/ I think that's the cheap one, retail from a dealership only around £10/litre, you need 2 litres.

What code is the gearbox?

Blah, blah, blah...

The last two paragraphs before the green/orange tables are what I was referencing mainly. @Camlobe, can you give an example of this 'frankly dubious' content? (And your reasons for doubt)

^ Interesting and good info about reducing both weight and hazardous substance content by going smaller. All you tend to hear about is car manufacturers fitting smaller batteries to 'penny-pinch' but it seems there are other pressures too. Do you @BigEjit know of a source of reliable freely available info about charging AGMs etc. optimally? Every time I look it up I seem to find more conflicting info. One site suggests that they must be protected from overcharge more so than conventional lead acids, and protected from heat by avoiding fitment in engine bays - https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm Based on that it seems that poor lifetimes may be partly due to car manufacturers siting of these batteries near engines?

It's always struck me as being 'make-up for cars'.

I wonder if something is recorded in the relevant electronic control unit when these events happen? Probably.

Trouble is with this, you're unlikely to get many contributions from people saying e.g. "I was busy on my mobile whatsapping a hilarious youtube link to my mate Dave when the XYZ safety system cut in and definitely prevented me crashing head-on with a car coming the other way. You should have seen the other driver's face, he looked terrified LOL" … "Great safety systems in these cars, innit". And yet those 'saves' might outnumber the false triggers by 100-1 for all we know.

Is it item 9 here? M5 x 16mm? https://skoda.7zap.com/en/cz/yeti/yet/2013-666/8/867-867065/

I'm sure I didn't pay as much as this, but it was a handful of years ago. https://www.amazon.co.uk/Slpro-Wheel-Bearing-Assembly-Puller/dp/B01LWSTTVP/ref=sr_1_3?dchild=1&keywords=72mm+wheel+bearing+tool&qid=1603440394&sr=8-3 Get a quote from a garage, but not one that will just use a press to fit the new bearing, without the appropriate Gen2 bits to push in the right place, cos you/they will end up doing it again after they knacker the new bearing. I think the only bit likely to suffer from cheap metal in the Chinese kits is the main 'pull' bolt, but if you grease it thoroughly, and maybe heat the bearing carrier with a sustained blast of hot air before attempting removal you'll be OK. They do take a bit of starting during removal, so probably expect to be using a long breaker bar on that 'pull' bolt if you do DIY. Maybe not so bad with added heat, which I didn't use on my one and only experience.

The slide/guide pins don't take the rotational forces, it's the edges of the pad backplates resting against the sitcky-outy prongy bits of the bearing housing that do that, as far as I can see.

Try pulling the cubby right out/off. I think if you push it sideways you can pop one side off at the hinge, then the other. Looks like the design of the plastic stuff changed after that thread; probably with the 2004 facelift. Actually easier way. I see a VCDS cable there. Plug it in, go to module 09, see what part number it says it is.

Pin 1 at wiper - brown - earth to chassis Pin 2 at wiper - green/white -- to pin 4 of a ten-way connector in left side of boot Pin 3 at wiper - green/red - to pin 5 of same ^ connector Pin 4 at wiper - black - to pin 3 of same ^ connector (originating from ignition live fuse no.40)

Or the crankcase ventilation system, more likely.

That all looks like a ton of fun.

I guess you could run some logs of the engine ECU's 'view' of the brake pedal switch and see if you get false switch activations corresponding with the cruise oddities? And/or the Central Electrics module view of the brake light switch. (Think I've remembered those right, apologies if not).

Ah, that makes more sense.

Bloody Hell! £11 here when I last bought one, admittedly a few years back. PM me.