Alternator and brake fluid lights ... Possible charging issue

[MattR]

Hi,

Our Mk 1 312D Mercedes Sprinter's alternator and low brake fluid lights have been coming on when the engine is started. On both occasions, they have gone off after a few mins of driving over 40mph.

The first time this happened, I didn't notice the lights come back on again when I slowed down. They did this afternoon when I was driving through town.

The battery was too low to start the vehicle this morning - I assumed because we hadn't moved for a week and we has been charging our phones from the engine battery.

We had been on electrical hookup once during the week but since our fridge isn't working on 12 or 240v and the control panel reported that the engine battery was still showing 3 green lights out of 5, we thought that the battery was fine; it wasn't. When I tried to charge up the engine battery via the electrical hook today, I noticed that the engine battery charging ligh didn't come on on the panel - I guess that the battery was too low to take a charge from the EHU.

I have purchased a heavy duty battery charger and reconditioner and had it recharging for approx 2 hrs; the level showed as 60%. We were then offered a jumpstart... The alternator and low brake fluid lights stayed on until I got to 40mph. We've driven to the next campsite (around 30 mins over 40mph) then the lights came on again as we slowed into town. They didn't go off when I got back up to 40mph though. I put the battery back on charge and it still said 60% (ie no noticable change following the drive). I've put the battery on a recondition sequence and it should start charging once that's finished. Fluid levels including brakes are fine.

Can anyone advise what would cause both the alternator and brake fluid lights to come on and go off simultaneously and whether any of the other symptoms - such as the fridge not working on 12 and 240v are linked?

Apart from the lights and not starting, there's no other indication that the vehicle has any issues; acceleration and breaking has been fine

 

[jockaneezer]

The first thing you must do is put a multi meter on your battery and see what voltage the alternator is delivering with the engine running, you should be looking for at least 14 volts.

 

[cmcardle75]

Hi,

Our Mk 1 312D Mercedes Sprinter's alternator and low brake fluid lights have been coming on when the engine is started. On both occasions, they have gone off after a few mins of driving over 40mph.

The first time this happened, I didn't notice the lights come back on again when I slowed down. They did this afternoon when I was driving through town.

The battery was too low to start the vehicle this morning - I assumed because we hadn't moved for a week and we has been charging our phones from the engine battery.

We had been on electrical hookup once during the week but since our fridge isn't working on 12 or 240v and the control panel reported that the engine battery was still showing 3 green lights out of 5, we thought that the battery was fine; it wasn't. When I tried to charge up the engine battery via the electrical hook today, I noticed that the engine battery charging ligh didn't come on on the panel - I guess that the battery was too low to take a charge from the EHU.

I have purchased a heavy duty battery charger and reconditioner and had it recharging for approx 2 hrs; the level showed as 60%. We were then offered a jumpstart... The alternator and low brake fluid lights stayed on until I got to 40mph. We've driven to the next campsite (around 30 mins over 40mph) then the lights came on again as we slowed into town. They didn't go off when I got back up to 40mph though. I put the battery back on charge and it still said 60% (ie no noticable change following the drive). I've put the battery on a recondition sequence and it should start charging once that's finished. Fluid levels including brakes are fine.

Can anyone advise what would cause both the alternator and brake fluid lights to come on and go off simultaneously and whether any of the other symptoms - such as the fridge not working on 12 and 240v are linked?

Apart from the lights and not starting, there's no other indication that the vehicle has any issues; acceleration and breaking has been fine

TBH, it sounds like the alternator or associated drive belt. The battery may or might not also be knackered, but I'd suspect alternator first.

 

[MattR]

The first thing you must do is put a multi meter on your battery and see what voltage the alternator is delivering with the engine running, you should be looking for at least 14 volts.

I've been lent a meter that plugs into the ciggy socket - that should do similar shouldn't it? It is displaying 12.1V but I don't want to start the engine until the reconditioning and charging sequences finish.

I'll try in the morning.

 

[cmcardle75]

TBH, it sounds like the alternator or associated drive belt. The battery may or might not also be knackered, but I'd suspect alternator first.

But do check all the connections are tight, first, both positive and earth. Battery, alternator and starter motor, and the engine earthing straps.

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[RobertJary]

I've been lent a meter that plugs into the ciggy socket

I've got one of these; mine always reads low, maybe by as much as 0.4V

 

[MattR]

An update....

The charger has been charging for at least 22 hrs... M it started off showing 60% charge and that hasn't changed all day. I forgot to check the voltage from that battery but will shortly.

I was able to start the engine first time this evening - no problem with that but the alternator and brake fluid lights came on and stayed on.

With the engine running, I turned the headlights on and revved the engine - I've been told that if the alternator is fine, the lights should brighten when the engine is revved; they didn't.

I noticed a different noise after the engine was revved - not a noise I've heard before. Can anyone advise what this is likely to be caused by?

 

[GeoffnDee]

It is possible that the alternator pulley is spinning on its shaft causing the noise and lack of charge to the battery , the pulley may have a woodruff key that has sheared or if it has a taper it may be loose.
The lack of fridge operation on 12v may be linked to the alternator problem due to a lack of D+ signal from the alternator to the fridge/relay

 

[MattR]

It is possible that the alternator pulley is spinning on its shaft causing the noise and lack of charge to the battery , the pulley may have a woodruff key that has sheared or if it has a taper it may be loose.
The lack of fridge operation on 12v may be linked to the alternator problem due to a lack of D+ signal from the alternator to the fridge/relay

Is that likely to a difficult or straightforward repair please?

 

[GeoffnDee]

The alternator would need to be removed to fix or replace the pulley (which could be faulty, but not to expensive) and although I do not know myself how difficult removal is on your van they are normally straightforward to remove as they do need to be repaired/ replaced sometimes.
It should be possible to confirm that the pulley is the problem before removing the alternator as I think the pulley is being turned by the belt but the pulley is not turning the alternator shaft as it should. The pulley may have a clutch in it that is faulty (these alternator pulleys can be found on e-bay at a reasonable cost if that is the type you have)

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[GeoffnDee]

Mattyjwr I do not know how to do do links but if you look at e-bay item No. 274858386644 you should see a freewheel pulley with possible faults that can happen when faulty in its description.

 

[Lenny HB]

You would be better off buying a cheap multimeter and checking the voltage directly on the battery. Just looking the headlights is not really conclusive as the alternator output does not rise much with revs.

IMO battery reconditioning chargers are a waste of time. If a battery is knackered, it's knackered and needs replacing not worth messing about.

 

[MattR]

You would be better off buying a cheap multimeter and checking the voltage directly on the battery. Just looking the headlights is not really conclusive as the alternator output does not rise much with revs.

IMO battery reconditioning chargers are a waste of time. If a battery is knackered, it's knackered and needs replacing not worth messing about.

Thank you. I was told by another camper on site that the alternator test with revving engine and lights could help but I used the ciggy socket meter this morning and it's displayed 13V after being off charge for 9hrs. I'm wondering if the lights didn't change because the battery was already at or close to full voltage so the light difference wasn't noticeable.

The battery is back on charge and the charger is showing 80% having been displaying 60% all of yesterday.

We're heading towards a town where multimeters might be more available today but from the new noise heard last night, I'm thinking that the alternator pulley system is the culprit. This is all new to me - I've not had alternator problems before.

 

[cmcardle75]

Hi,

Our Mk 1 312D Mercedes Sprinter's alternator and low brake fluid lights have been coming on when the engine is started. On both occasions, they have gone off after a few mins of driving over 40mph.

The first time this happened, I didn't notice the lights come back on again when I slowed down. They did this afternoon when I was driving through town.

The battery was too low to start the vehicle this morning - I assumed because we hadn't moved for a week and we has been charging our phones from the engine battery.

We had been on electrical hookup once during the week but since our fridge isn't working on 12 or 240v and the control panel reported that the engine battery was still showing 3 green lights out of 5, we thought that the battery was fine; it wasn't. When I tried to charge up the engine battery via the electrical hook today, I noticed that the engine battery charging ligh didn't come on on the panel - I guess that the battery was too low to take a charge from the EHU.

I have purchased a heavy duty battery charger and reconditioner and had it recharging for approx 2 hrs; the level showed as 60%. We were then offered a jumpstart... The alternator and low brake fluid lights stayed on until I got to 40mph. We've driven to the next campsite (around 30 mins over 40mph) then the lights came on again as we slowed into town. They didn't go off when I got back up to 40mph though. I put the battery back on charge and it still said 60% (ie no noticable change following the drive). I've put the battery on a recondition sequence and it should start charging once that's finished. Fluid levels including brakes are fine.

Can anyone advise what would cause both the alternator and brake fluid lights to come on and go off simultaneously and whether any of the other symptoms - such as the fridge not working on 12 and 240v are linked?

Apart from the lights and not starting, there's no other indication that the vehicle has any issues; acceleration and breaking has been fine

It is sounding even more like the alternator. I've never replaced just a pulley, though, always the entire alternator. They usually cost about £100. Ease of replacement depends on the location. Changing the one on my wife's Polo took just 5 minutes. Officially you needed to remove the air con compressor first, but a little wiggle got past that obstruction. Some are a nightmare.

 

[MattR]

It is sounding even more like the alternator. I've never replaced just a pulley, though, always the entire alternator. They usually cost about £100. Ease of replacement depends on the location. Changing the one on my wife's Polo took just 5 minutes. Officially you needed to remove the air con compressor first, but a little wiggle got past that obstruction. Some are a nightmare.

We've had it tested this morning. The alternator has failed. We're at a garage where the mechanic is trying to source a replacement. He has quoted €370 and it will be completed in 2 hrs once the alternator arrives this afternoon.

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[Lenny HB]

If the starter battery has been flattened a couple of times it would be best to replace it.

 

[GeoffnDee]

Mattyjwr Shame the alternator did not just need a new Alternator freewheel clutch pulley @ £25.34 but at least the new Alternator should have many other new parts in it , last you for a long time , and have a warranty with it.
Also if you have brought a multi-meter it will not go to waste as it may be useful in sorting your fridge problem out , or any others in the future, if the new alternator does not fix things , as I hope it does.

 

[MattR]

Mattyjwr Shame the alternator did not just need a new Alternator freewheel clutch pulley @ £25.34 but at least the new Alternator should have many other new parts in it , last you for a long time , and have a warranty with it.
Also if you have brought a multi-meter it will not go to waste as it may be useful in sorting your fridge problem out , or any others in the future, if the new alternator does not fix things , as I hope it does.

Many thanks. I liked the idea of the freewheel clutch pulley, especially the price.

I have multimeters at home and used to carry one in the camper but took it out as I never needed it previously when on the road.

 

[cmcardle75]

Mattyjwr Shame the alternator did not just need a new Alternator freewheel clutch pulley @ £25.34 but at least the new Alternator should have many other new parts in it , last you for a long time , and have a warranty with it.
Also if you have brought a multi-meter it will not go to waste as it may be useful in sorting your fridge problem out , or any others in the future, if the new alternator does not fix things , as I hope it does.

In reality, the total cost (which will be largely labour) would remain mostly the same, as you'd have to pay the mechanic to swap the pulley over and, as you say, you also get the benefit of the new alternator.

 

[MattR]

Just as an update.... The alternator was replaced in 30 mins (it would have been a bit shorter but the mechanic was struggling to get the fan belt back on. Total time spent with me was approx 1 hr.

The alternator was the biggest cost (€305) as there aren't many cheap alternatives available in France (supply issues generally compounded by holidays). The rest of the bill was approx €60 labour, tax and "waste disposal" or "refurbishment tax". Total €385.

The strange sound has gone, the alternator and brake warning lights turn off when they should and the battery charges.

Thanks to all who gave info and suggestions.

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