Keying of connector looks right for both original Bosch and Valeo alts here. Perhaps that 140A alt really isn't 'drop in' compatible with your car, what part number does it have?

The Bosch 140A is as follows: BR14 -C-L F and then OOM 144 197. I connected it up on the floor under the car, with a suitable earth, and the battery warning light on the dash did not illuminate. I then tried the same with the Valeo and the warning light did illuminate. This did not please me. Tomorrow, I shall take both alternators to a friend who is gifted in the field of electronics and he will discover what is going on with them and possibly get both of them working. He told me the other day that he has even been repairing LED light bulbs! I don't suppose there is much wrong with either of them.

Edited 20 March, 20251 yr by TinyTim

3 minutes ago, TinyTim said:

The Bosch 140A is as follows: BR14 -C-L F and then OOM 144 197

No VW group part number to be seen? That number looks like just the brushpack/voltage regulator part.

There are definitely no other serial numbers on it. That is indeed the regulator part number.

Things aren't going well! The Bosch alternator is a dud. One of the slip rings is knackered. My friend has checked out the origial Valeo 110A (VW AG 03F 903 023 E or Valeo TG11C086) and he reckons the diodes are all good, as are the slip rings and brushes, so it must be the regulator. The regulator/brush packs for these seem to start at about £52 on Ebay, whereas similar looking ones can be as little as £25. New alternators locally are from £145 and not much better on Ebay. Any suggestions? Is the Bosch 140A of any value, needing new slip rings and maybe a regulator brush pack? Only cost me £30 via Marketplace. Seemed nice folks!

The Bosch one can surely be refurbished, but it's not a quick and easy job, especially the first time you try. A few youtube vids exist, showing what's involved.

I've done a couple, one including slipring change IIRC, back when I had bags of spare time. Doubt I'll do another.

We seem to be on a bit of a parallel path. The one I tested on my Polo today was that same 03F...E part number, bought from ebay, but I need it to replace a broken one in a car I hope to buy tomorrow.

Noticed that the back cover of these Valeo versions don't have screws or nuts holding them on, just plastic fingers that slide down threads, making disassembly more difficult.

Parts catalogue actually says that the regulator/brushpack is a 'no replacement part available' from Skoda. Possibly because of these push-on fixings for the cover.

Higher price for the reg may be just down to selling fewer due to this apparent 'harder to service' design.

Edited 21 March, 20251 yr by Breezy_Pete

I'm a bit of an old skinflint. I've repaired and serviced my cars for over 50 years. I even still fit my own tyres. Had I not wasted £30 on a dud, I'd be easier (but not much!) about paying £145 for a new one. £52 is too much to gamble on the regulator when there's no guarantee it will work. There's an 03F.....023E on Ebay from a breaker for £36, but some clot has broken the socket! Must be why it's so cheap. It's about a week now since I took the alternator off and my wife is getting fed up with the saga! Why does a 1.2 TSI need such an expensive alternator? I found a Ridex remanufactured one on Autodoc for £86 plus carriage. That sounds good until you read that this does not include the refundable 'core charge' of over £300 for the old unit! Seriously! Who goes for that! I wonder if I could get away with fitting a 70amp or 90amp unit from an earlier model. Why the heck do they need 110amps? Small cars had 35A or 45A back in the day!

I expect there's quite likely to be other versions including same or lower rated ones, perhaps a 110A Bosch that would fit.

Will have a browse of the parts catalogue next time I'm upstairs near the 'big internet'.

The only other part number that explicitly says for CBZA, CBZB engines without start/stop (which I assume matches your requirement) is 03F 903 023D, which is a 140A Bosch item.

May be worth broadening your ebay/scrappie search to include that one.

Thanks.

Bought a brand new WAI alternator locally and fitted it. I'm still not getting 14V with the engine running! I'm now wondering if the problem could be with the ECU which it communicates with. Perhaps that isn't sending enough volts down the exciter wire.

Further to my last post, I now understand that you can't measure the volts with a smart alternator like you would with a conventional a fixed-charging alternator. It may be that the old alternator was faulty and the battery does now stay charged. I'll see how it goes.

I'm pretty sure you don't and shouldn't have a smart alternator. The car doesn't have start/stop functionality, right?

On 21/03/2025 at 18:00, TinyTim said:

I'm a bit of an old skinflint. I've repaired and serviced my cars for over 50 years. I even still fit my own tyres.

You are not alone!!!!

Having fitted some 50 or more new tyres what has been a real eye opener is that not a single one has needed balancing when fitted or later in service. I remove all the old balance weights and carefully align each tyre using the coloured dots, something I hav never seen a tyre fitter do.

9 minutes ago, J.R. said:

You are not alone!!!!

Having fitted some 50 or more new tyres what has been a real eye opener is that not a single one has needed balancing when fitted or later in service. I remove all the old balance weights and carefully align each tyre using the coloured dots, something I hav never seen a tyre fitter do.

I fiited two new ones this morning. Yet again, no balancing required! It wasn't like that in the old days. Test-driven and smooth.

24 minutes ago, Breezy_Pete said:

I'm pretty sure you don't and shouldn't have a smart alternator. The car doesn't have start/stop functionality, right?

The auto-electrician told me it had a smart alternator, which is why he couildn't test it off the car. I'll check this out!

A smart alternator is only used on cars with start/stop and EFB or AGM batteries. I seem to remember reading on here that UK market mk2 Fabias never came with such things.

Sorry if we've covered this before, but does the battery light illuminate when the ignition is switched on?

24 minutes ago, TinyTim said:

I fiited two new ones this morning. Yet again, no balancing required! It wasn't like that in the old days. Test-driven and smooth.

You are right, the manufacturing is much better.

12 hours ago, Breezy_Pete said:

A smart alternator is only used on cars with start/stop and EFB or AGM batteries. I seem to remember reading on here that UK market mk2 Fabias never came with such things.

Sorry if we've covered this before, but does the battery light illuminate when the ignition is switched on?

Yes, the battery light illuminates and goes out when the engine is started. It did that with the original alternator. It's just that my voltmeter showed 12.87V with the engine running and 12.54 when I switched on the headlamps and I was expecting 14V.

There may be a rather poor connection somewhere between alternator and battery. Can you prize off the plastic cap from the alternator output terminal and measure directly there, carefully, to be sure of not shorting probe to anything unintended? Red probe on that stud, black probe on alternator alloy body. If that's nice and 14.3-ish, but the voltage across battery posts is much less, you will have confirmed a poor connection.

The strip fuse at the battery end of the alternator output cable isn't blown, is it?

Measure volts on cable end of it and compare with voltage at other end (above it in image).

I've been working on my Rover 75 today and driving the Skoda, which didn't go flat. I will carry out the checks you suggest. Thanks.

I haven't been working on cars today, but I've just done some research online. The new alternator I bought is a WAI 20588N. That is a LIN-bus controlled alternator, which is otherwise known as a smart alternator. It is computer controlled. The WAI 20588N is the correct one for the car, replacing the Valeo TG11C086 (VWAG 03F 903 023E). I can't find a full Valeo spec. to confirm that the TG11C086 is LIN-bus controlled, and nor can I find it under the VW AG number.

You bought the wrong alternator, unfortunately. Who told you it was correct? Please don't say ECPs look-up by reg number...

Please confirm explicitly that your car does not have start/stop.

If so, the 03F 903 023E original alternator does not have a LIN connection. It has the blue exciter wire and the other DFM wire.

I'll take my old 03F 903 023E to work with me this morning and see how readily the brushpack can be replaced. Found one for about half the price you mentioned, I think.

See this page for independent verification that Valeo TG11C086 is a conventional alt, with L and DFM connections, not LIN, because you don't seem to trust what I am saying very much:

A3508S | Alternators

Just researching brushpacks now. Edit: if you click on the blue font TG211C086 part number on that page, it takes you to a page with all the parts including Valeo and their aftermarket replacement regs. Top website.

A few options here, presumably the aftermarket replacement: Valeo Are3010 for sale | eBay

This one had every right to be struggling, major wear to sliprings and brush protrusion near zero.

Inner brush appeared to be just still making contact.

Not sure if you've tried, but the back cover prises off relatively easily, I just warmed up the plastic around the two M5 stud a bit first.

Then there are two M5 screws (8mm head) and one double stud with 7mm hex middle to remove regulator/brushpack.

Edited 28 March, 20251 yr by Breezy_Pete

eBay

ARE3010 AS-PL Alternator Regulator | eBay

HITACHI 2500731. HITACHI 130731. REFERENCE OEM NO VALEO YR1616VFP1. VALEO YM2660VP2F. VALEO YM16. VALEO YM1687VFP1. VALEO YM1672VFP1.

^ Cheapest reg I've found thus far.