General Alternator Warning Light

[estcres]

I have a Fiat Ducato 2.8 TD, 1999, and the alternator light is playing up.

When the ignition is turned on all the warning lights appear as normal, Start the engine and after a second or so all warning lights go out with the exception of the Handbrake warning light. So far OK.

Release the handbrake and all warning lights are out, you can then drive away and everything appears OK. After a while the Alternator warning light starts to glow, not very bright but it still glows.

The light will suddenly go off and remain off for a long period, up to 30 miles or so and then suddenly start glowing again.

Going over rough ground and bumps in the road do not have any effect at all, if it's on it remains on and if it's off it remains off.

I have carried out the following checks

Checked the voltage output and this is 14.58 - 14.68 volts, even when the light is glowing.

The alternator drive belt is tight and is not slipping.

The battery voltage is 12.6 volts at rest and 13.2 volts just after a charge.

The engine temperature remains at a constant 80 degrees with no signs of overheating.

I have just returned from a 2000 mile trip in France and even with the light glowing suffered no adverse effects.

Advice is low on the ground and has consisted of, faulty alternator, faulty rectifier, bad or broken earth, bad connection.

Has anyone suffered this problem before or give any further advice.

Thanking you in advance for any advice you can give me.

 

[mervyncp]

I see you never got an answer on this. You've probably sorted it by now, but:-

Sounds like a regulator problem.
I had something similar which was ok for about 3 years and 30K miles. It then stopped charging all together.
Get it checked at a local auto electrician, for peace of mind if nothing else. It should be repairable

HTH

Mervyn

 

[witzend]

I have the same problem with my x250 for last 3500 miles have removed alternator had it tested and no fault found my light is now permanently on and still charging at 14v I could live with the light but the leisure battery's are not getting any charge

 

[varesecrazy]

I see you never got an answer on this. You've probably sorted it by now, but:-

Sounds like a regulator problem.
I had something similar which was ok for about 3 years and 30K miles. It then stopped charging all together.
Get it checked at a local auto electrician, for peace of mind if nothing else. It should be repairable

HTH

Mervyn

I had this on ALL of my tipo / tempra cars back in the day,
( so dim it was only obvious at night),
never actually stopped charging..WAS a regulator problem,

I would change this anyway..,
however if it's putting 14.4V into the engine battery - I believe your non-charging of the leisure battery is a different issue,
Charlie

 

[rayc]

I suspect the leisure battery is not getting any charge because the D+ signal from the alternator is not as required to operate the split charge system. Does the fridge still work on battery?
The faults are interrelated, when the charging lamp problem is sorted out then the D+ signal problem should also clear. The lamp has 12v supply to it and when the engine is not running an earth connection is provided via the alternator which operates the lamp. When the alternator is running then the earth is replaced by 12v so the lamp has 12v on each side and goes out. The same 12v is the D+ signal which operates the split charge system and fridge, entry step etc.

 

[varesecrazy]

I suspect the leisure battery is not getting any charge because the D+ signal from the alternator is not as required to operate the split charge system. Does the fridge still work on battery?
The faults are interrelated, when the charging lamp problem is sorted out then the D+ signal problem should also clear. The lamp has 12v supply to it and when the engine is not running an earth connection is provided via the alternator which operates the lamp. When the alternator is running then the earth is replaced by 12v so the lamp has 12v on each side and goes out. The same 12v is the D+ signal which operates the split charge system and fridge, entry step etc.

thanks for putting that into relatively simple terms,

I can almost understand that now,

cheers,
Charlie