hi we have got a fiat ducato 2007 the problem we are having is the van wont charge. we have replaced the battery and alternator but still there lies a problem. there is NO battery light displaying at all on the dash does anyone have a wiring diagram for this model please?

Does the battery light not come on even if the engine is off

More detail please. What model/variant, is it standard van or motorhome with dual battery? Have you checked for power to main B+ stud on alternator? If this is dead, the main fuse may be blown.
I've attached diagram for 3.0L. I don't know if the others are the same, haven't got time to check at the moment.

On that diagram the exitation voltage for the alternator comes in on terminal D+. If there is no battery light when the ignition is first switched on this voltage could be absent in which case the alternator will not begin charging.

FYI
Caution, this system appears to be controlled by the BCM. Don't short wires to earth or power, don't use a test light on CAN, BCM, ECU, etc. circuits.

cartronics said:

hi we have got a fiat ducato 2007 the problem we are having is the van wont charge. we have replaced the battery and alternator but still there lies a problem. there is NO battery light displaying at all on the dash does anyone have a wiring diagram for this model please?

Click to expand...

My Ducato had the same problem, replaced battery but still went dead or below starting volts.
Then one pitch black night walking back to vehicle I noticed the rear camera had a couple of circular led red lights on So I now disconnect it each time I leave the van, never had a problem since, thats presuming you have one.

same problem here with 2004 Ducato.
Replaced battery and alternator. But it seems to be random.
I can start and with engine running get 14.2 Volt and it stays around this but most of the time the voltage drops slowly over time below 12V! When I stop the engine and restart, the voltage goes up again.
Is there anything else besides the alternator regulator which diconnects the battery from the charging circuit? Like an unloader relay?

The only thing in the path from alternator to battery on your 2004 is the fuse on the +ve battery terminal. I guess you could bypass it or at least check all connections are bright and shiny. The other path of course is the earth via the engine earth strap to body and the battery earth to body. You can for testing purposes run a jump lead from alternator body direct to battery negative and see if it changes the voltage when it is running low. The voltages you're measuring, are these at the battery or at the alternator output?

DucatoMiltonKeynes said:

The only thing in the path from alternator to battery on your 2004 is the fuse on the +ve battery terminal. I guess you could bypass it or at least check all connections are bright and shiny. The other path of course is the earth via the engine earth strap to body and the battery earth to body. You can for testing purposes run a jump lead from alternator body direct to battery negative and see if it changes the voltage when it is running low. The voltages you're measuring, are these at the battery or at the alternator output?

Click to expand...

thanks for your help.
All measured at the battery. I have visually checked all the earth straps and they look good but know that I have to test them properly to be sure.
When I fitted the new alternator I measured at the alternator and battery and there was no difference. But then it only ran for a few minutes.
It's really random, sometimes the voltage is good for 100 miles and other times it starts to drop after 10miles of driving.
The strange thing to me is that as soon as you use the starter, the voltage is going up.
I have to switch the ignition off and start the engine with the starter, tried to bump start it while rolling (ignition off-ignition on) and that makes NO difference to the voltage, it stays where it was before I switch ignition off.

Looking at your screen name, are you a garage by any chance? I am from Dunstable.

I used to own a garage years ago, but now I do engineering. It looks very much like a bad contact which welds itself back in place when you draw heavy current with the starter. I would bolt on a heavy-ish cable straight onto the alternator bracket or engine and right onto the battery negative terminal and bypass all the earth straps to see if that cures it. Often it's finding out what's wrong by elimination! Another thing that can cause intermittent faults are the battery terminal clamps. Make sure all's clean and there are no cracks in them or slightly loose connections where the leads enter them.

DucatoMiltonKeynes said:

I used to own a garage years ago, but now I do engineering. It looks very much like a bad contact which welds itself back in place when you draw heavy current with the starter. I would bolt on a heavy-ish cable straight onto the alternator bracket or engine and right onto the battery negative terminal and bypass all the earth straps to see if that cures it. Often it's finding out what's wrong by elimination! Another thing that can cause intermittent faults are the battery terminal clamps. Make sure all's clean and there are no cracks in them or slightly loose connections where the leads enter them.

Click to expand...

I repaired the battery clamps when I bough the motorhome and had the battery out the very first time. They are a joke in my opinion, they hardly worked, Icould pull the earth off without undoing the clamp.
I will attach a small voltmeter permanently to the alternator output to monitor the voltage against the battery voltage.
I have also found that the motorhome builder has tapped very badly into the D+ of the alternator wire to feed the split charge relay. But I have a LED installed in this line to monitor that the split charge was actually working when the engine is running and it always did.

I hope I can find the problem before we head off to France. Last year we drove home from Italy through the Gotthard tunnel (10+ miles length) with the lights off and 11.5 Volt on the gauge.....

Can you recommend a garage around Dunstable? I need a front wheel bearing changed.

Good idea to monitor both voltages to see what's happening. I would definitely put on another direct engine to battery earth lead and it would do no harm at all to leave it on permanently. If you are getting a break in the alternator charging circuit, this can take out the alternator voltage regulator, so better safe than sorry.
As far as I know, your bearing will need to be pressed out with a hydraulic press, so unless you can afford a Fiat/Peugeot/Citroen dealer, any fairly big independent garage will have what's needed. Try to get a recommendation of a local garage from someone you know if you can.

With most smart charge alternators the charging voltage is controlled by a pwm signal from the ecu/pcm/bsi, if you disconnect the pwm signal the voltage should default to 14.4V or thereabouts.

You are the man!

Followed your advise and connected a jump lead from alternator housing to battery minus pole. Bingo! Voltage went up to 14.4 -14.5 and stays there rock solid no matter lights on or off.

I removed the earth leads I could reach (battery to ground)and cleaned them, but this didn't make any difference. I used the jump lead to "override" the engine to chassis ground strap which made no difference.

Followed your other advise and made a permanent earth lead from alternator bracket (there was a suitable hole) to chassis where the short minus lead from the battery attaches. That seems to be ok. Tomorrow I will go for a ride and see what happens.

Again, many thanks for your help. :worship:

DucatoMiltonKeynes said:

Good idea to monitor both voltages to see what's happening. I would definitely put on another direct engine to battery earth lead and it would do no harm at all to leave it on permanently. If you are getting a break in the alternator charging circuit, this can take out the alternator voltage regulator, so better safe than sorry.
As far as I know, your bearing will need to be pressed out with a hydraulic press, so unless you can afford a Fiat/Peugeot/Citroen dealer, any fairly big independent garage will have what's needed. Try to get a recommendation of a local garage from someone you know if you can.

Click to expand...

You're welcome and it sounds like we're on the right track, then! The actual fault could be invisible internal corrosion inside a connector at one end of an earth strap. It doesn't take much resistance to drop the charging voltage down whenever it decides to work loose. Using the starter motor heats up the bad contact and temporarily welds the bad junction together until vibration shakes it loose again.
As you've now bypassed all of that with a single cable, you can just leave it if you want to and it should be fine as long as it can take the current of the starter motor if it needs to.
Bypassing is done by auto electricians all the time. There can be 2 fuses, 3 junctions, 4 connectors, 2 metres of cable and a switch between the battery and the wiper motor, for instance. You could spend a day not finding a connection that sometimes fails. Much faster and more dependable to run a couple of new wires from the correct fuse to where it needs to go.
I hope it all keeps working well for you!

I am not surprised about the earth problem on my Ducato, there was still white paint work on the connection point for the earth lead on the chassis! Fiat doesn't even bother to mask that spot up before painting the shell. Or was it just an oversight?

I tried removing the big flat earth strap on the engine (which is GREEN and brittle) but the bolt felt "soft" when I tried to loosen it and I decided to leave it alone.

I have used 20mm2 cable for now but may get a larger one later when I have some more time.

They probably relied on the threads of the bolt breaking the paint and making the earth connection. Just lazy. Same goes for the engine earth strap. The engine doesn't earth well through the exhaust system, which is all you have left if the engine earth strap fails. It'll be a good idea to clean up the metal where the battery earths for the good of all the other electrics in the van and let your bypass cable sort out the starting and charging and other things like the engine oil pressure switch which earth to the chassis on one side.Maybe this thread will help solve the problem for others. I bet this has happened to more people.

I have cleaned the earthing point under the battery tray. This is where I attached my bypass earth as well to have a direct connection to the battery.

I have been out today and can report that the voltage is rock solid 14.3 - 14.5 ! No matter what I switch on or off. The engine now starts much better, the starter motor seems to spin much more eager. Engine starts with a flick of the key, great!!!

Well, I wish I would have asked you before I sunk almost £400 in the drain to sort this problem.
At least I now have a much bigger alternator and a fresh battery. Bring it on Holidays!

At least you found the problem before you spent another £400. Sounds like you're set up for many years of reliable motoring now - just like it should be!

Hello, We repair Motorhomes, specialising in Motorhome electronics/charging systems and are seeing a lot of Fiat Motorhomes with poor Earth connections. I know this is an old post, but still relevant now.

The issue we see most is that the earth lead itself is corroded inside the Crimped on Eyelet, i.e. where the Steel eyelets at each end crimp over the Copper cable. Hence why most of the time dismantling and cleaning the traditional Earth point makes no difference as the issue is the cable itself.

If you cut open the eyelets on failed cables you will most likely find the Copper cable badly corroded, even though the cable looks perfect from the outside. We usually see a Green and White mess inside.

What we think is happening is that the cable is Copper and the Eyelets a different metal, often steel, causing galvanic/dissimilar metal corrosion in the presence of Water. On the Fiat X250 the Gearbox earth strap it is low down in the Road/Salt Water spray.

Because the Fiat straps are made using dissimilar metals, it will only be a matter of time before they fail. Even replacements.

The Poster above found cleaning his Earth connections made no difference, but fitting a secondary new Earth strap did, confirming the cable itself is the issue, not it's contact point on the Engine. We think running a new cable is a better solution as a new Fiat version will only fail again over time.

Note that 'failure' is gradual, usual beginning at around 3 years by introducing voltage drop when charging the habitation batteries. This voltage drop worsens and then Starting problems may begin, but not always. The voltage drop/charging problem worsens on bigger battery banks.

One recent Motorhome we worked on had just 13.1v charge voltage at the Habitation battery (13.2v at the Starter battery) until we ran a new cable from the Battery negative to the Engine, which jumped both up to close on 14.4v.
Despite the obviously poor connection, no issue at all with Starting the engine. Starter still spun quickly.

There are Earth straps available on the web that have Copper cable AND Copper Eyelets so corrosion should not become a future issue.

When running a battery Earth lead high up on the engine away from Water spray we would expect a Copper/Steel cable to last 10 years, but only 3 years low down in the engine bay in the Water spray.


Be careful about detaching the Black Earth cable to the top of the Starter solenoid on pre X250 vehicles The strap bolt often requires a lot of effort to undo, but the solenoid is not the most sturdy of items, sometimes breaking away from the Starter leading to a big bill.
The Red Live lead comes into the left side of the Solenoid so care needed to not touch it with a spanner.

We suggest on this model you run a new chunky cable direct from the battery negative to the engine 'Lifting Eye'.

We identified why the cables were failing in 2015 and updated the numerous Motorhome forums, but I never thought to post it on here before.