Technical Alternator exciter wire...

[Stholt]

Hi all, our 2006 2.8 had the battery light come on and voltage at the battery was only measuring 11.8. The alternator looked original so I changed it to a new one. The alternator is still not putting out any voltage(there is battery voltage present at the alternator, currently 12.3). I checked the exciter wire and it does not appear to have any voltage going to it as well, I see this should be either around 0.7v or 12v...can't seem to get a clear answer. Anyone here ever had the same issue? I have battery voltage going to the alternator, so I know the mega fuse is fine, the battery light on the dash comes on, the van will start if the battery has enough voltage. Is there a fuse, or connector, or can anyone tell me where this wire goes so I can trace it without removing a whole bunch of stuff I don't need to?

This all happened while the brother in law was borrowing the van, which is still at his house an hour away, so having a plan before heading back over would be my preference.

Cheers, and thanks in advance!

 

[Communicator]

Hi all, our 2006 2.8 had the battery light come on and voltage at the battery was only measuring 11.8. The starter looked original so I changed it to a new one. The alternator is still not putting out any voltage(there is battery voltage present at the alternator, currently 12.3). I checked the exciter wire and it does not appear to have any voltage going to it as well, I see this should be either around 0.7v or 12v...can't seem to get a clear answer. Anyone here ever had the same issue? I have battery voltage going to the alternator, so I know the mega fuse is fine, the battery light on the dash comes on, the van will start if the battery has enough voltage. Is there a fuse, or connector, or can anyone tell me where this wire goes so I can trace it without removing a whole bunch of stuff I don't need to?

This all happened while the brother in law was borrowing the van, which is still at his house an hour away, so having a plan before heading back over would be my preference.

Cheers, and thanks in advance!

I cannot see the logic in changing the starter., but a newer item may perform better.

The alternator field circuit on the x244 is old style, simple, and not computerised, so easier to fault.

Since the battery light illuminates, it is receiving a supply. The light normally connects to the alternator field (D+) terminal, and grounds through the alternator field winding and regulator. This small current through the field winding gives the alternator the initial impetus to start generating. With the alternator generating the D+ terminal becomes live at nominal 12V. Voltage is equal at both sides of warning light, so it goes out.

There is the possibility of an earth fault on the D+ connecting wires.

More probable is worn brushes on the alternator, especially if it is original, and the odometer reading is over 50,000.
In this scenario no, or insufficient current passes through the alternator field winding, but the warning light may ground via the regulator sensing connection. (middle wire in diagram).

The main alternator fuse is the pink MIDI fuse.

I am attaching my marked up copy of eLearn diagram E5010. More details of connectors, including location may be available here, but the diagram and others are unreadable due to oversize script.

 

[Stholt]

I cannot see the logic in changing the starter., but a newer item may perform better.

The alternator field circuit on the x244 is old style, simple, and not computerised, so easier to fault.

Since the battery light illuminates, it is receiving a supply. The light normally connects to the alternator field (D+) terminal, and grounds through the alternator field winding and regulator. This small current through the field winding gives the alternator the initial impetus to start generating. With the alternator generating the D+ terminal becomes live at nominal 12V. Voltage is equal at both sides of warning light, so it goes out.

There is the possibility of an earth fault on the D+ connecting wires.

More probable is worn brushes on the alternator, especially if it is original, and the odometer reading is over 50,000.
In this scenario no, or insufficient current passes through the alternator field winding, but the warning light may ground via the regulator sensing connection. (middle wire in diagram).

The main alternator fuse is the pink MIDI fuse.

I am attaching my marked up copy of eLearn diagram E5010. More details of connectors, including location may be available here, but the diagram and others are unreadable due to oversize script.

Thanks for the reply, I don't know why I wrote starter...I have corrected the post. I have changed the alternator and the new alternator(not a rebuild) is not producing any voltage. Good earth point and the large post on the alternator test out to 12.3v, which is the same as the battery. It should be up around 14v. I will take a look at what you sent and try to plan.

 

[jackwhoo]

Symptoms suggest the wire from charge bulb is grounded somewhere before it gets to alternator, it is this wire that excites the alternator.

 

[jackwhoo]

If the op disconnects the excitor wire from alternator and charge bulb still lights with key on then it proves excitor wire is shorted to ground.

 

[Communicator]

If the op disconnects the excitor wire from alternator and charge bulb still lights with key on then it proves excitor wire is shorted to ground.

I was just writing a post with the same suggestion!

Given where this thread is posted, is the vehicle a motorhome/campervan? Some of these vehicles use a connection from the D+ to operate a fridge relay, and possibly a split charge relay. This gives more possible points for a short circuit to occur. I say some, because my 2006 2.8jtd PVC with CBE electrics does not use a D+ connection. However the converter had incorrectly connected to D+ instead of Ign +ve. The incorrect connection was to a black/yellow wire (diagram shows yellow/black) behind the rear (+ve) end of the battery.

 

[Stholt]

Thanks Jackwhoo I will try that when I am there. It is a 2006 Fiat Ducato Rapido 7086 campervan. Been running great up till now.

 

[jackwhoo]

Thanks Jackwhoo I will try that when I am there. It is a 2006 Fiat Ducato Rapido 7086 campervan. Been running great up till now.

I had not considered the moho factor.
Pay attention to @Communicator comments and find / isolate the D+ excitor wire from the habitation wiring to rule out a short there.

 

[Communicator]

At least some Rapidos use CBE electrical systems, which should not need a D+ connection. However my PVC, which also dates from 2006, was incorrectly connected to D+by the converter.

 

[Stholt]

Ok, so I just want to run my thoughts by you all:

The battery light comes on, so I know it is not the F37 fuse. I need to check for the D+ being shorted to earth/ground, after that I need to check for continuity from the bulb to the D+, if there is none, then I start checking each section of wire between the various connections....does this sound correct?

If I test for voltage on the alternator side of the bulb while it is lit, what should it be? I would assume from the diagram that the same voltage should be present at the D+ otherwise there is an issue.

Thanks again, hoping to head over early this weekend and get it sorted.

 

[Communicator]

As the warning light illuminates, then there is a circuit to somewhere, but that could be an earth fault.
Voltage at D+ when engine not running and light illuminated, will be minimal.

 

[jackwhoo]

Disconnect d+ at alternator if battery light still comes on then it is shorted to ground.

 

[Communicator]

Disconnect d+ at alternator if battery light still comes on then it is shorted to ground.

Necessary, but not that easy to access on a 2.8jtd!

 

[Stholt]

Necessary, but not that easy to access on a 2.8jtd!

No, no it isn't...but that is easier than tracing and testing sections of wire buried behind the battery and engine. Thanks for the suggestions all, I will come with hopefully good news

 

[daroya]

Hi all, our 2006 2.8 had the battery light come on and voltage at the battery was only measuring 11.8. The alternator looked original so I changed it to a new one. The alternator is still not putting out any voltage(there is battery voltage present at the alternator, currently 12.3). I checked the exciter wire and it does not appear to have any voltage going to it as well, I see this should be either around 0.7v or 12v...can't seem to get a clear answer. Anyone here ever had the same issue? I have battery voltage going to the alternator, so I know the mega fuse is fine, the battery light on the dash comes on, the van will start if the battery has enough voltage. Is there a fuse, or connector, or can anyone tell me where this wire goes so I can trace it without removing a whole bunch of stuff I don't need to?

This all happened while the brother in law was borrowing the van, which is still at his house an hour away, so having a plan before heading back over would be my preference.

바쁜 일상 속에서 피로가 쌓일 때는 집에서 편하게 받을 수 있는 마사지 서비스가 큰 도움이 됩니다. 전문 테라피스트가 직접 방문하여 개인 맞춤형 케어를 제공합니다. 은평구출장마사지 서비스를 이용하면 이동 없이도 편안한 휴식과 힐링을 경험할 수 있습니다. 근육의 긴장을 풀어주고 혈액순환 개선에도 도움을 줄 수 있어 만족도가 높습니다. 시간과 장소에 구애받지 않아 직장인이나 바쁜 현대인에게 특히 유용합니다. 집에서 편안하게 힐링 시간을 가져보며 몸과 마음의 균형을 회복해보세요.

This is almost certainly an exciter/field circuit issue, not the alternator. Since B+ is present and the new alternator still doesn’t charge, it’s not being triggered. The lack of voltage on the exciter wire points to a blown small fuse or an open wire between the fuse box/ECU and the alternator. Check the IG/ALT/CHARGE fuses first and then trace continuity on the exciter wire.

 

[Communicator]

This is almost certainly an exciter/field circuit issue, not the alternator. Since B+ is present and the new alternator still doesn’t charge, it’s not being triggered. The lack of voltage on the exciter wire points to a blown small fuse or an open wire between the fuse box/ECU and the alternator. Check the IG/ALT/CHARGE fuses first and then trace continuity on the exciter wire.

@daroya ,I agree that the fault is unlikely to be on the alternator. The fusing is proven by the fact that the warning light illuminates. The vehicle in question is a motorhome, and the possibility of a short circuit to earth on the exciter wire, should not be forgotten. It has been suggested that the OP disconnects the D+ at the alternator to prove/disprove the presence of an earth fault, which could be caused by the failure of a diode connected in parallel with the coil of a relay used in the motorhome conversion.

@Stholt , I assume that the lack of news is due to the journey time to your Rapido, and perhaps the weather conditions?
I know that at least some Rapido MHs use CBE electrical systems, but can you confirm what yours uses?

 

[Stholt]

This is almost certainly an exciter/field circuit issue, not the alternator. Since B+ is present and the new alternator still doesn’t charge, it’s not being triggered. The lack of voltage on the exciter wire points to a blown small fuse or an open wire between the fuse box/ECU and the alternator. Check the IG/ALT/CHARGE fuses first and then trace continuity on the exciter wire.

Was just out looking at it today, there is 10.8v at the exciter wire IF it is not connected to the alternator. As soon as it is connected, voltage drops to 0.16v. I am thinking it is a corroded wire somewhere. I have checked the section of wire from the alternator to the first connector, even jumped it out with a piece of wire, but the same issue. Trying to find out where the wire goes after that connector as ELearn does not seem to be fully updated for the later X244 ducato wiring. I am.half tempted to just find the wire after the dash bulb and splice in a new wire, but I would really.like to correct it properly.

 

[Communicator]

Was just out looking at it today, there is 10.8v at the exciter wire IF it is not connected to the alternator. As soon as it is connected, voltage drops to 0.16v. I am thinking it is a corroded wire somewhere. I have checked the section of wire from the alternator to the first connector, even jumped it out with a piece of wire, but the same issue. Trying to find out where the wire goes after that connector as ELearn does not seem to be fully updated for the later X244 ducato wiring. I am.half tempted to just find the wire after the dash bulb and splice in a new wire, but I would really.like to correct it properly.

To quote member Ocwobio, who also has a 2.8jtd, "Using eLearn is like peeling the layers off an onion."

Have you located diagram E5010 "Starting and Recharging". Scrolling down and from the daigram and clicking on the appropriate connector, gives pin arrangement and connecting wire details including destination connector. I have used this facility to trace the cluch pedal switch connection to the ECU, at that particular connection does not appear on any diagram. Perhaps the art is in choosing the correct alternative, when several are given.
After almost 20 years, I have not positively located connector D097 "Short Circuiting Coupling" which I retranslate as "Linking Connector). I have glimpsed a possible candidate forward of the radio, but almost inaccessible.

Edit To add: Modern multimeters are very sensitive, and will show a plausible voltage reading when connected via a high resistance. With this in mind 10.8V seems low, when the only significant resistance is the warning bulb, and assuming that it has a tungsten filament, the resistance should be quite low, when not glowing.

 

[Stholt]

I am beginning to see that...seems to be plenty of information, but getting to the correct info for what I need is trying. I did take the instrument cluster off to try to find the white wire that come from the bulb, and then follow it out, but the loom is wrapped in that cloth tape and all the other connectors are behind and under the dash, seems nearly impossible to get to. If I can definitely isolate the wire coming out of the battery bulb, then I will probably splice in a replacement wire there and just run it down to the exciter post. Not ideal, but if it is safe and works properly then it will do.

 

[Communicator]

I am beginning to see that...seems to be plenty of information, but getting to the correct info for what I need is trying. I did take the instrument cluster off to try to find the white wire that come from the bulb, and then follow it out, but the loom is wrapped in that cloth tape and all the other connectors are behind and under the dash, seems nearly impossible to get to. If I can definitely isolate the wire coming out of the battery bulb, then I will probably splice in a replacement wire there and just run it down to the exciter post. Not ideal, but if it is safe and works properly then it will do.

There are errors in eLearn! You seem to have found one. Diagram E5010 has the wire leaving the instrument panel as white, while diagram E4010 for the instrument panel is less informative. However the wiring details for the instrument panel connector B pin 1 show it as "HM" or grey/brown, the same as shown for the alternator end on diagram E5010. The wiring info for the instrument panel connector E050B does have pin 1 routed to D097A pin 8, which is what diagram E5010 suggests. If my memory serves, instrument panel connector E050B is second from LHS. It is a 12 way, and pin 1 will be at one corner. It seems that the wire may be grey/brown instead of white.

Before running a new wire you may wish to investigate the "Alternator Coupling", connector, D007A. It is only 2 pole with the second pole being used to the oil pressure switch (Grey/Yellow wire). Location is shown as close to the rear of the battery, which makes it more susceptible to corrosion, than those behind the dash. Perhaps some contact cleaner may work, who knows?