Technical Need a new alternator but my local garage can't find the right part (1999 1.9 TD)

[jtonky]

Hello all, I have a 1999 Fiat Ducato 1.9 TD (Motor Home) and the Alternator is overcharging the battery. Does anyone know of a good "vintage" parts dealer as I am struggling to find one online?

This issue, causes the battery warning light to come on and when it's on all the electrics (Indicators specifically) stop working. Stop the Van and everything is fine as the battery is not being overcharged.

My local garage has had 3 alternators delivered for a 1.9 TD but they are all wrong with the wrong measurement for the mounts and whilst they are looking I wondered if the community had any recommendations.

Otherwise, we might have to go down the refurb route which could be costly.

Thank you in advance.
John

 

[cid]

Hi, I got an alternator for my 1996 1.9td from Direct Auto Electricals in Manchester tel. 0161 873 8300. Worth a call. I got mine a couple of years ago and no trouble so far. all the best Ian

 

[varesecrazy]

Hi

Your problem lies with the regulator.. which also carries the brush pack..

AND IS A BOLT ON PART

I used to swap these on all my old marelli alternators

 

[Communicator]

Hello all, I have a 1999 Fiat Ducato 1.9 TD (Motor Home) and the Alternator is overcharging the battery. Does anyone know of a good "vintage" parts dealer as I am struggling to find one online?

This issue, causes the battery warning light to come on and when it's on all the electrics (Indicators specifically) stop working. Stop the Van and everything is fine as the battery is not being overcharged.

My local garage has had 3 alternators delivered for a 1.9 TD but they are all wrong with the wrong measurement for the mounts and whilst they are looking I wondered if the community had any recommendations.

Otherwise, we might have to go down the refurb route which could be costly.

Thank you in advance.
John

Hi John,

I cannot understand as to how the warning light becomes illuminated, if your alternator is overcharging the battery. The battery and alternator voltages will be similar. This means that there should only be a very small voltage across the indicator light.

May I suggest the alternative possibility that you have a faulty ignition switch, or have you been able to measure the excessive battery voltage?
I am speculating that a reverse feed from the alternator D+ via the warning light, may be sufficient to keep the engine stop solenoid operated.

Stopping the engine and restarting could temporarily reset the hypothetical ignition switch problem.

 

[jtonky]

Hi John,

I cannot understand as to how the warning light becomes illuminated, if your alternator is overcharging the battery. The battery and alternator voltages will be similar. This means that there should only be a very small voltage across the indicator light.

May I suggest the alternative possibility that you have a faulty ignition switch, or have you been able to measure the excessive battery voltage?
I am speculating that a reverse feed from the alternator D+ via the warning light, may be sufficient to keep the engine stop solenoid operated.

Stopping the engine and restarting could temporarily reset the hypothetical ignition switch problem.

Thank you for your reply. It measures 15.6 but the battery light does not always show all the time. I read some where that the light comes on when it measures a difference or drop so I suppose id it drops from 15.6 to 14. It might trigger . Don't know.

 

[Communicator]

Hi John,
I am sorry for the delayed reply, but I am using my PVC this week.

Your reading of 15.6V is of course too high, and may confirm the diagnosis made by @varsecrazy of a faulty regulator. This was also my first thought, but I am still unable to understand how this can give both too high a voltage and illuminate the warning lamp, unless the regulator is failing in different ways at different times, which seems unlikely.

The basics of the alternator (battery) warning light are fairly simple. With ignition ON, and the engine stopped the alternator will not be generating. In this state, a small current will flow from the battery, via the ignition switch to the warning light, to the alternator D+ (field) terminal, and thence via the alternator field (rotor) and brushes to the regulator and chassis (earth). The light is illuminated. When the engine is started. this small current provides an essential start up supply for the alternator field, and the alternator starts generating. With the D+ terminal now at the same voltage as the battery (B+), there is no voltage difference across the indicator light, hence no current flows. The light goes out.

In some fault conditions the current may possibly flow in the opposite direction through the warning light, if there is a voltage difference. This could perhaps occur if the supply to the ignition switch goes faulty when the engine is running. It may be possible for a small current to flow from the alternator D+, through the warning light, and to chassis via the engine stop solenoid, and keep the engine running. However I cannot yet see as to how this would give your 15.6V.

I do not have a diagram for the charging circuit on your vehicle, but I am attaching one applicable to my x244 JTD. If your ignore all the various fuses, and substitute an engine stop solenoid for the ECU, the basic principles are the same. (The text annotations are mine.)

Perhaps your best course of action would be to try a new regulator, but as I have been trying to explain, I have reservations about the warning light illuminating.

 

[jtonky]

Hi John,
I am sorry for the delayed reply, but I am using my PVC this week.

Your reading of 15.6V is of course too high, and may confirm the diagnosis made by @varsecrazy of a faulty regulator. This was also my first thought, but I am still unable to understand how this can give both too high a voltage and illuminate the warning lamp, unless the regulator is failing in different ways at different times, which seems unlikely.

The basics of the alternator (battery) warning light are fairly simple. With ignition ON, and the engine stopped the alternator will not be generating. In this state, a small current will flow from the battery, via the ignition switch to the warning light, to the alternator D+ (field) terminal, and thence via the alternator field (rotor) and brushes to the regulator and chassis (earth). The light is illuminated. When the engine is started. this small current provides an essential start up supply for the alternator field, and the alternator starts generating. With the D+ terminal now at the same voltage as the battery (B+), there is no voltage difference across the indicator light, hence no current flows. The light goes out.

In some fault conditions the current may possibly flow in the opposite direction through the warning light, if there is a voltage difference. This could perhaps occur if the supply to the ignition switch goes faulty when the engine is running. It may be possible for a small current to flow from the alternator D+, through the warning light, and to chassis via the engine stop solenoid, and keep the engine running. However I cannot yet see as to how this would give your 15.6V.

I do not have a diagram for the charging circuit on your vehicle, but I am attaching one applicable to my x244 JTD. If your ignore all the various fuses, and substitute an engine stop solenoid for the ECU, the basic principles are the same. (The text annotations are mine.)

Perhaps your best course of action would be to try a new regulator, but as I have been trying to explain, I have reservations about the warning light illuminating.

Hello, very grateful for your reply! It's odd as seemingly at random it comes on when you start the engine and the indicators don't work... it's very odd. Then on other days, like the day i took it to the garage other than a high voltage it worked. We are now looking to get the Alternator refurbished, including the new regulator and so I will keep all posted on how things go.

 

[jtonky]

I have not been able to use the van very much and the issue does not always show but had a break through i think supporting the ignition switch as an issue. The warning light came on during my last trip and I wobbled the key whilst driving and it went out.

Next job is to work out how easy it is to DIY or to find a garage.

 

[The Panda Nut]

It mat just be a loose connection on the switch or minor earth issue. Worht a prod. I have done a variety of non Fiat ignition switches. None were difficult but some had one way shear bolts that had to be cut and new bolts fitted to replace. Some have key switch separate to steering lock. I had a helpful local locksmith rearrange the lock tumblers on one so I could keep my original key.

 

[Communicator]

I have not been able to use the van very much and the issue does not always show but had a break through i think supporting the ignition switch as an issue. The warning light came on during my last trip and I wobbled the key whilst driving and it went out.

Next job is to work out how easy it is to DIY or to find a garage.

As I have previously explained, I can see the possibility of a faulty ignition switch causing the warning light to illuminate. However I would not have expected that the relatively small current taken by the warning light from the D+ node, would reduce the voltage significantly, and cause the regulator to increase the current flowing through the alternator rotor (field), so that the output voltage increased to the previously measured 15.6V.

Provided that you are sure that the ignition switch is faulty, it would be sensible to change the switch, and then check the result before changing the alternator or regulator.

 

[jtonky]

As I have previously explained, I can see the possibility of a faulty ignition switch causing the warning light to illuminate. However I would not have expected that the relatively small current taken by the warning light from the D+ node, would reduce the voltage significantly, and cause the regulator to increase the current flowing through the alternator rotor (field), so that the output voltage increased to the previously measured 15.6V.

Provided that you are sure that the ignition switch is faulty, it would be sensible to change the switch, and then check the result before changing the alternator or regulator.

Hello just by way of an update, I took off the surrounds for the ignition switch and found one of the plugs was a bit loose. I think it was the yellow one. I noted if you pulled it out then you got a battery alarm but not quite like the one I was having. Anyway as I said I cannot re-create the issue on demand and we haven't had cause to use the van a lot recently. However so far so good it looks like it may just be a case of a loose cable connector. Typically the issue seems to happen when we are fully loaded on our way some where but it's been on day trips etc and all
Ok. I'm not counting my chickens yet but I'm just monitoring it I wanted to share this issue in case anyone else had it.

 

[jtonky]

View attachment 413127
Hello just by way of an update, I took off the surrounds for the ignition switch and found one of the plugs was a bit loose. I think it was the yellow one. I noted if you pulled it out then you got a battery alarm but not quite like the one I was having. Anyway as I said I cannot re-create the issue on demand and we haven't had cause to use the van a lot recently. However so far so good it looks like it may just be a case of a loose cable connector. Typically the issue seems to happen when we are fully loaded on our way some where but it's been on day trips etc and all
Ok. I'm not counting my chickens yet but I'm just monitoring it I wanted to share this issue in case anyone else had it.

Ok the batter warning finally came back and would not go away. I traced it down to the earth wire. I opened the plastic case and inspected it. The aluminium connector wad heavily oxidised. I used a small screw driver to scratch the contact points and squashed it a bit so it would connect tight. and put it bag together. Problem solved .

 

[Communicator]

Hi John,

I was interested to read of your discovery. I have often used pliers on female blade connectors, but was surprised that you found aluminium connector blades? on ignition switch.
In this context green/yellow wire colour code does not indicate an earth connection. With ignition on it will be live at 12V, with probably no fuse between it and the battery.

With my curiosity aroused I have checked against a copy of the wiring diagram extracted from the German x230 Workshop Manual that is available in the downloads section. Unfortunately the diagrams which have two sections schematic and wiring, which are mutually inconsistent. My preference would be for the schematic, but the wiring which is harder to follow seems to make more sense. However on the wiring section I can trace connection 1070 through colour changes at connectors to the instrument panel, and similarly from there to your yellow/green wire at the ignition switch. It seems that this wire is the connection from the ignition switch to the battery warning light.

I am still puzzled as to why you were able to measure over 16V at the battery. The exact position of both of your test prods is not visible in your photo. Grasping at straws, is it possible that for convenience you were measuring across the terminal clamps, and not at the lead alloy conical battery terminals. This could be significant.

I am attaching a pdf copy of the appropriate diagram, to which I have added a translation of the German colour codes. Even if it does not help you directly, others may find it useful.

 

[jtonky]

Hi John,

I was interested to read of your discovery. I have often used pliers on female blade connectors, but was surprised that you found aluminium connector blades? on ignition switch.
In this context green/yellow wire colour code does not indicate an earth connection. With ignition on it will be live at 12V, with probably no fuse between it and the battery.

With my curiosity aroused I have checked against a copy of the wiring diagram extracted from the German x230 Workshop Manual that is available in the downloads section. Unfortunately the diagrams which have two sections schematic and wiring, which are mutually inconsistent. My preference would be for the schematic, but the wiring which is harder to follow seems to make more sense. However on the wiring section I can trace connection 1070 through colour changes at connectors to the instrument panel, and similarly from there to your yellow/green wire at the ignition switch. It seems that this wire is the connection from the ignition switch to the battery warning light.

I am still puzzled as to why you were able to measure over 16V at the battery. The exact position of both of your test prods is not visible in your photo. Grasping at straws, is it possible that for convenience you were measuring across the terminal clamps, and not at the lead alloy conical battery terminals. This could be significant.

I am attaching a pdf copy of the appropriate diagram, to which I have added a translation of the German colour codes. Even if it does not help you directly, others may find it useful.

Hi thanks for the detailed message a diagram.
Yes I was most likely measuring across the terminal in that I put the probes into the top.

Battery warning light makes sense as when the battery warning light comes on, the indicators stop
Working it everything else was ok. V annoying it was!

I am not metal expert but I got the idea as I have an x5 BMW at home and it's a know problem with the tail lights as BMW used aluminium plates to mount the bulb which you connect the light wire into ... the connection point gets oxidised as you have to sand paper it to make it work again.

So my connector on the camper was visibility dulled so perhaps exposure to current for so long, compared to all the others which looked shiny . Also it could have just worn loose so maybe squashing it so it made a tight connection. Which would make senses if it was loose as it would come on and go off again. It did not have any white Powdery stuff on it so perhaps it was not aluminium.

Anyway hope this helps some one who is driven mad by the same thing