Hi Folks

 

It seems the alternator in my daughter's 2013 Monte Carlo is overcharging at 17v. From doing some searching, I understand that the regulator could probably be replaced rather than the whole alternator. Is that right and how easy is it to do? Is the regulator inside or bolted to the casing or something?

 

TIA

Hi,

pls pm me your reg No.

yes you can replace the regulator, simple task once the alternator is out of the vehicle, doubt its possible to do it in situe. Its bolted on the back usually and held on by a few small screws or bolts and significantly cheaper than an new alternator. Ideally should be done as soon as possbile to avoid blowing bulbs left right and centre and "possibly" damaging ECU's and or battery.

 

You can get regulators with or without brush kits, I would go for the later as it's out. Just need the Part number on the alternator label to get the right regulator.

 

This is "probably" it......(with brushes)

 

https://www.ebay.co.uk/itm/01G184-ALTERNATOR-Regulator-Skoda-Fabia-Rapid-Roomster-Yeti-1-2-1-4-TSI-1-6-TDI/253149832808?hash=item3af0e7e668:g:IXUAAOSwhDdXENRI:rk:5:pf:1&frcectupt=true

 

This is what I can see of the label with it in situ. It was a garage that told me if was charging at 17v and then later on they told me it was back at 14v so I don't know if they got it wrong or if something intermittent is happening. I have a meter, so I'll test it a few times before taking the plunge.

 

That may well be the case. If the voltage regulator is faulty, it will not regulate the voltage. it may well fluctuate from one extreme to another at will!

What lead you to suspect a problem with the alternator in the first place?

 

Looking at this page, and using the part number in your photo, your alternator is option 12, or 14 in the list of alternator variants. Scrolling miles down towards the bottom of that list, you'll find that the regulator is available as part number 06B 903 803 B

Various offerings on ebay at quite different prices.  If I remember rightly, the Valeo ones like yours are a bit more of a faff to fit than on the Bosch alts, but nothing too challenging.

 

****Hold up. Weirdly, although the alternator part numbers appear to be the same for options 12 and 14, (first two digits are cut off for some reason, unhelpfully), option 14 says "no replacement part:" for the regulator when you scroll way down the list to the individual parts.  So you're better off - if you haven't already - following Lyminton's advice as he can get better info, I think.

 

What's your engine code? One of these: CBDB, CFHA, CFHC, CFJA, CAYA or one of these: CBZA, CBZB ?

 

 

 

Edited 21 January, 20197 yr by Wino

Only had a faulty regulator on a motorbike but it’s better to get it replaced sooner than later otherwise you’ll end up frying your battery too and I can’t imagine it will do the canbus any good either. 

Bad earths can affect the regulator too so clean up and tighten the earths within the engine bay including the battery terminals. Once you’ve done this run a multimeter across the battery terminals and measure the voltage at various RPM's. It should never go above 14v. If that’s good no problems if not check the positive to various earths and finally to alternator output positive to earth. Use clips instead of probes if delving into the engine bay to avoid injury. 

I understood that if you car has energy saving features as most seem to now, the alternator is designed to give out a higher voltage ( 15+v ) under control of the ECU.

 

The idea being that the battery is held at about an 80% charge, then during braking the ECU raises the alternator charge voltage to use the alternator as a suplementary brake.

 

Don't think it's meant to get to 17v though.

On 21/01/2019 at 10:24, CWARD said:

Only had a faulty regulator on a motorbike but it’s better to get it replaced sooner than later otherwise you’ll end up frying your battery too and I can’t imagine it will do the canbus any good either. 

Bad earths can affect the regulator too so clean up and tighten the earths within the engine bay including the battery terminals. Once you’ve done this run a multimeter across the battery terminals and measure the voltage at various RPM's. It should never go above 14v. If that’s good no problems if not check the positive to various earths and finally to alternator output positive to earth. Use clips instead of probes if delving into the engine bay to avoid injury. 

 

Most alternators on a good charging system and a healthy battery will often give out 14.2 - 14.5 V with no loads on, any higher than that would be a concern.

@UrbanPanzer cheers for the correction