Battery Light on C4

[MelC4]

After driving mistakenly with Alternator 5 pin plug out for 5km battery light has come on and battery is not charging is there a fix for this.

[Peter.N.]

If everything is connected now sounds like the alternator is faulty. If charging correctly you should have about 14.4 volts across the battery with the engine running. Its most likely the regulator/diode pack that's gone faulty, much cheaper than an alternator (look on Ebay) and usually very easy to fit.

Peter

[MelC4]

Thank you will have a look I did manage to get of once but it came back on next day whilst driving.

[Dormouse]

How is the car driving now? Fitting a test voltmeter you can see while driving is a bonus but it must connect to the battery not through any accessory plugs.

[MelC4]

The car is driving but draining the battery is it a big job to change the alternator regulator/diode pack.

[Peter.N.]

Depends on the car, recently did one on a 406 a real pig but the one on the C5 looks easier. On some cars you can change the pack with the alternator in situ but if you have to take it off fitting the electronic pack only takes a few minutes.

Peter

[MelC4]

Hi how many diodes the C4 pack need.

[Peter.N.]

I think possibly 6 as it has a three phase output but they are not easy to change. The complete regulator assembly is held in with 2 screws or maybe 3

Peter

[MelC4]

Hi Peter thanks for that info, I tried to find that diode kit nothing here in Australia anything from Uk is normally taking 4 to 5 weeks without these holidays coming up, anyway I tried Marc BSI resetting procedure and I have managed to clear the fault with no charge and the battery light staying on I did this on Sunday also but it came back on Monday I now 14.15v on alternator and 13.83v on battery terminal with a full load on let’s hope it stays away.

[Peter.N.]

I hope so! Sorry didn't realise you were in Australia or I would have been more sympathetic. Have you looked on ebay or do they all come from here?

Peter

[MelC4]

After 5 minutes the battery light and no charge fault is back anyone have any idea how to fix it.

[Dormouse]

Hi Mel. I have looked and there are a large range of similar alternators fitted to, obviously, PSA vans and cars, VW Group and a good sprinkling of other European vechicles. So, get your alternator make and number - you may need a mirror on a stick. Then enter the part number/make into local suppliers and autoshops online enquiries and see if you can either get it repaired or get a service pack or a new or secondhand alternator. Best of luck.

[MelC4]

Hi Dormouse after doing a reset with the positive battery terminal I have managed to clear the fault with no charge and the battery light staying on but it came back after 4 days so I have repeated this today and now the fault has gone again can this really be the alternator or another problem, does anyone know a fix for this fault.

[Dormouse]

It has the signs of an intermittent Wiring/Alternator fault and I have no knowledge of anything else on your car that might cause this issue without throwing up other codes/faults.

[Dormouse]

MelC4 has this list of faults.

I found this article in FCF

and this generic OBD advice

Does anyone have a suggestion of where to start for MelC4. I have said Wiring/Alternator and he has visually examined the harness/boxes.