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Help get us home from the Alps! (Auto Electrics)


Citizenfish

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We are currently in the Alps in our motorhome, how we made it I don't know. I'm not sure we're going to make it back unless someone can help solve this total mystery.

 

Van is a coachbuilt on a Fiat 2.3 diesel, 2008 (Ci conversion)

 

Our charging system is failing but appears to be failing randomly. We drove from swindon to Dover fine and stopped the van waiting for the ferry. Then I started it to drive on and got the battery warning light. I thought this was odd but ignored it. Driving off the ferry warning light again. We stopped in a layby and I measured voltage over the battery, 12.4 volts. Not good as it should be 14v with the alternator going.

 

I stopped then started the van and the voltage went up to 14v. So we decided to keep going.

 

We then drove 200 miles and stopped for diesel. Starting the van, warning light comes on again. No amount of fiddling or fuse pulling can get it to go away. Our only choice was to gamble, so we drove another 120 miles until the battery was near flat (I have a spare) and camped for the night.

 

Next morning, the van just about manages to start on the old battery, and guess what 14v at the battery. We drive 300km and stop for diesel. Start again and the warning light is back on.

 

The only link I can make is a warm engine is causing it and there is some sort of relay/cut-out circuit that is killing the charging current to the battery. There must be a split charging circuit as the leisure battery charges when we are moving.

 

We notice that if we put the fridge to DC charge, the light stays lit for ten seconds after starting then it switches off completely after we hear a relay click.

 

I have 4 days to fix this before we head home. I'm pretty certain the alternator is ok (when it works) as it is brand new (replaced in Feb).

 

What else should I check? I cannot find the schematics for the van online and don't have them with us. Any other ideas most greatly appreciated.

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Thanks Keith

 

During the long periods when it did work the charging was fine and the light did not flicker once. So it charged perfectly when warm for several long periods.

 

I wonder if there is some relay that flips the charging current between van/leisure battery and if this circuit is failing somehow. Could that be it? Surely the alternator would never be connected to both simultaneously?

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I'd have a discharge test done on the battery firstly. It may be just the battery on its last legs.You will have a reading of 14 volts when the engine is running as you're getting the reading off the alternator and not the battery.

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Citizenfish - 2013-03-25 6:38 PM

 

Thanks Keith

 

During the long periods when it did work the charging was fine and the light did not flicker once. So it charged perfectly when warm for several long periods.

 

I wonder if there is some relay that flips the charging current between van/leisure battery and if this circuit is failing somehow. Could that be it? Surely the alternator would never be connected to both simultaneously?

 

No there will not be a relay switching between the 2, the engine battery is always connected via the original Fiat wiring and the leisure battery is 'added in' when the split charge relay is activated by either the ignition warning light wiring or a rise in voltage, most likely the former.

 

You should find the split charge relay and fridge relay somewhere near the engine battery, try unplugging both relays and/or associated fuses to see if it makes any difference.

 

Keith.

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Thanks Keith. This would seem to point at a faulty alternator then which sometimes works fine and sometimes doesn't work at all. Only thing puzzling me is why I would ever get a green light at the fridge if it wasn't working?

 

Anyone have any idea of the relay location as I have no schematics with me?

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Or is it a faulty engine earth? This has been reported several times on the X2/50 vehicles.

 

With the engine running measure the voltage between the a good earth point on the engine and the battery negative. Also try measuring when you crank the engine. Any reading will indicate a faulty earth.

 

Keith.

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Sounds identical to the fault I had on my last car alternator was charging interminably until if finally gave up , The rectifying diodes had been dying in the alternator. Although its a new alternator it still could be faulty.

 

Also worth following up Keith's advice and checking the earths. The earth strap between gearbox and chassis is a known problem on x250's often causes spurious electrical faults.

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An intermittent problem as you describe can be well worn alternator brushes. The black carbon ones that are used to regulate the charging current supplied to the rotor, and thus the alternaror output.

 

The fault can manifest itself as follows:-

 

The light coming on and off as you describe.

 

Also when you have a problem of the light being on with the engine running, please switch the engine off, then ignition only on (do not start the engine) and check if the alternator charge light is on, as it normally is. If the light does not come on then the fault will be worn brushes, a final check is to start the engine and the light will come on as you describe.

 

The intermittent nature of the fault, if as described, will be due to the brushes being worn to the point of partial failure and not total failure.

 

An old trick to get out of trouble on a tempory basis was to give the alternator a bit of a tap on the casing with a hammer, this can have the effect of loosening the brushes and allowing them to touch the slip ring.

This trick also worked on dodgy starter motors.

 

Hope the above helps, mike

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I've had this symptom on a couple of vehicles over the years.

 

I suggest you start with an obvious possible cause, before needing to go to the more complex...........

 

 

 

First and really simplest check is to ensure cable connections on battery terminals are REALLY clean and REALLY TIGHT.

Wiggle the clamp connections hard. Any movement at all, and they are too loose.

Ideally, remove the clamps from the terminals, clean, sand the contacts and clamps, and re-attach. (Make sure you've got any radio codes etc to hand in case you need to re-enter them after disconnecting/reconnecting engine battery.

 

In a roadside emergency, you can even tap the top of the clamp connectors lightly with a small hammer etc (watch you don't short the live connection to anything metal near the battery!) to ease them a smidge further down & tighter onto the battery terminals.

 

 

 

 

The battery connections not being clean enough and tight enough was the actual cause of the intermittent battery-light-on problem both times for me.

 

Good luck.

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I would put it down to sticking or badly worn brushes which run on a slipring. It is not unkown for brushes sticking in their housing due to carbon dust and muck. Try tapping the main housing of the alternator with the wooden shaft of a hammer. This may loosen them.
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ps. We have got Red Pennant. Just don't want to go through all of the hassle of a full recovery and roadside wait if we can help it.

 

pps. apologies for posting multiple topics, that one was down to well dodgy wifi at the campsite!

 

pps. I really really appreciate all the help. Without these ideas I would never have naled it myself

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ps. We have got Red Pennant. Just don't want to go through all of the hassle of a full recovery and roadside wait if we can help it.

 

pps. apologies for posting multiple topics, that one was down to well dodgy wifi at the campsite!

 

pps. I really really appreciate all the help. Without these ideas I would never have naled it myself

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ps. We have got Red Pennant. Just don't want to go through all of the hassle of a full recovery and roadside wait if we can help it.

 

pps. apologies for posting multiple topics, that one was down to well dodgy wifi at the campsite!

 

pps. I really really appreciate all the help. Without these ideas I would never have naled it myself

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So glad you're all sorted and thanks for the reply in triplicate :D :D :D

 

Stay in touch and let us know when you get home, I'm sure we'd all like to know that you make it back safely.

 

And don't forget that there is a wealth of knowledge on this forum freely available at almost any time of night or day!

 

Keith.

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Ok, we've just made it home.

 

My "bodge" earth strap worked for 700km but the problem re-occured with 90km to go before Calais. Luckily we had plenty of charge and some mucking about fixed it at Dover.

 

I think the second problem was that my temp. replacement was a thick audio earth cable and two ring connectors (all I could get in France) which became loose as it was heated up. I'll be sorting a proper earth strap this week and making sure it is fixed for good.

 

I am right in thinking that the engine earth is only done in one place? With the short strap just below the fuse box on the right hand side of the engine looking from the front of the van.

 

Thanks once again all.

Dave

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Citizenfish - 2013-03-31 7:23 PM

 

Ok, we've just made it home.

 

My "bodge" earth strap worked for 700km but the problem re-occured with 90km to go before Calais. Luckily we had plenty of charge and some mucking about fixed it at Dover.

 

I think the second problem was that my temp. replacement was a thick audio earth cable and two ring connectors (all I could get in France) which became loose as it was heated up. I'll be sorting a proper earth strap this week and making sure it is fixed for good.

 

I am right in thinking that the engine earth is only done in one place? With the short strap just below the fuse box on the right hand side of the engine looking from the front of the van.

 

Thanks once again all.

Dave

 

 

 

 

Well done for getting through the problem!

 

 

AFAIK it doesn't matter where the engine earth is, so long as it's a BIG earth strap, attached at both ends really clean and tight.

Certainly, you only need one engine-to-chassis earth cable

 

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