Breezy_Pete

I'll be glad when they foxtrot oscar.

3 of these passed low over me at about 5pm yesterday. Landing approach, a few minutes apart. Apologies for offtopicness. I'm sure these wars will be helping countries to reduce reliance on fossil fuels. There, I feel better now.

You can probably pick up a replacement alarm horn very cheaply on the secondhand market. Much easier to just change that than start from scratch. Car alarms are almost useless anyway, immobiliser does the work these days.

Doesn't it already have a factory fitted alarm?

True enough.

Getting the trim panels off and back on again is much easier if you pull the door seals front and rear well out of the way first.

That window motor is a passenger side unit from a Left Hand Drive T5 Transporter, so not the correct part for your Roomster. That can't be made to work fully/correctly despite fitting OK mechanically. It should be 6Y1959801, and the last line of the label should be SK258DDRS, not VW750PDLS. I'll message you to discuss options.

If it's the original radio it won't need a code entering after battery reconnection, it'll just sort itself out. The engine ECU won't lose anything either. It is mainly Haynes playing it safe. The airbag system (which includes seatbelt pre-tensioners) won't be active unless ignition is switched on, so just don't do that and you can leave battery connected.

I think VW group relays with 53 in big font on the top of them are super-common. Might be able to find a replacement on amazon prime (seeing several options there searching 141951253B), or in a local scrapyard pretty easily.

If battery warning light is working and no other problems are apparent, it will be fine to leave it as is.

Here's the section of circuit diagram covering this connector pair. T2w is the connector pair in your blue ring. It should have a brown/red wire coming from the alternator connector (T2v/2 labelled DFM above) which changes to lilac/green at T2w/2 as it continues on towards the engine ECU. [27] indicates a continuation on another page of the diagrams. The excitation (D+) wire is blue all the way form alternator connector to the T18a/9 connection which is in the cabin, at a control unit that would be called the BCM in modern parlance. Repair both, ideally using pre-wired 'proper' waerproof connectors (part numbers are on each half, in tiny writing), or just bypass the connector pair.

They go to the alternator. The blue wire is the excitation, which helps the alternator boot-up when engine is first started, the other is a signal wire from the alternator to the engine ECU, telling the latter how hard the alternator is working to satisfy electrical demands on a continuous basis. If the blue wire breaks, the battery light doesn't illuminate when ignition is switched on, and you would not get any warning if the alternator output fails. If the other one fails, some Fabia variants will display the ASR warning light after 10 minutes of driving. Cars that lack traction control/anti-slip regulation do not show any warning lights but a fault code will be present in the engine ECU if interrogated. It's odd that the blue wire doesn't appear to connect to a blue wire at the black two-wire connector. How does your battery light behave?

You will keep the original coilpacks as spares, right? Seems wrong to throw away functional items.

What makes you think the discs need replacing?

That turns out to be consistent with the parts catalogue. For your VIN, the number you quoted is complete without any suffix. It has been superseded by 5K0 907 659, but that's not the key point. Circuit diagrams for your date of manufacture (28.08.13) show no sign of the output being a LIN bus signal. Searching through Yeti circuit diagrams that I have, as far as mid-2016 still don't show a LIN output version air quality sensor, so I suspect that this model never changed over, unlike in that thread I linked above. I suspect the item you've bought suits LIN-based air quality sensor systems instead. Try to match your exact part number, or the superseding one above, and ignore any that have suffixes after the main 9 characters.