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Loss of D+ / Ignition on feed.


ian81

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on our 2008 Fiat Ducato 130 multijet based Buestner Aviano with Schaudt electrics the leisure batteries are not getting charged from the engine and the electric mirrors have stopped working.

It would appear that the AD01 unit is not getting the relevant  signals from the Ducato. I have checked the three System EI fuses in the engine bay and they are all ok.

Any thoughts?

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This was a common  fault  with that year Van the D+ cable on route from  alternator to ECU used to rub thru below the ECU where it leaves the loom coils around the ECU mount before coming up to the ECU this part of the mount gets rusty and the cable movement causes it to rub thru and short. Is your engine battery still getting charged if ign light is on just check the power at cigarette lighter with engine running should be around 14v my ign light was on when I had this fault for a long time but engine battery still was getting  charged (drove home from Portugal)

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12 hours ago, Labby said:

It could be worth checking if there is a 2amp (along with a 20amp)fuse close to the starter battery.  Also is there a D+ signal at pin 1 plug B4 on the AD 01 ?

..there are 50amp and 20amp fuses (intact) next to the battery.  Suspect 50 amp feeds the main Schaudt ebl. Not sure of the role of the 20a.

There is no D+ signal  on pin1 (should go to 12v on ign on and drop to zero on engine running). But there is no 12v at ign on on pin 2.  (incidentally the position lights switched by pin 3 is working)

 

 

10 hours ago, witzend said:

This was a common  fault  with that year Van the D+ cable on route from  alternator to ECU used to rub thru below the ECU where it leaves the loom coils around the ECU mount before coming up to the ECU this part of the mount gets rusty and the cable movement causes it to rub thru and short. Is your engine battery still getting charged if ign light is on just check the power at cigarette lighter with engine running should be around 14v my ign light was on when I had this fault for a long time but engine battery still was getting  charged (drove home from Portugal)

Cant see any evidence of chafing. Starter battery is charging properly -no red light- and 14.2 on the lighter socket.

But still no 12v at the A01 on ignition on.

 

Thanks for your help.

 

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The suggestion above is worth a check.

However, I would have thought that the mirrors would have worked via the "ignition on" signal, and the split-charge via the D+ signal to the AD01.

Do you have position/side marker lights, and do they work when the road lights are turned on?

These are controlled by yet another (lights on) signal into the AD01, and if these are also non-functional, then the thing to check would be the main 12V feed to the AD01.

The AD01 contains a number of fuses (separate ones for the D+ and ignition-on fed items which makes me doubt that a single fuse has gone if indeed the mirrors are controlled by ignition on). I think the main 12V feed is fused externally in that feed, and possibly adjacent to the vehicle battery? (but, of course, the location may vary by converter). 

 

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There is sometimes a converters power socket fitted by Fiat , with ignition feed supply etc , these are found at the bottom of the right hand front door B pillar on vans but if you have one fitted could it be around the front seat area ? (right hand side) 

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14 minutes ago, Labby said:

There is sometimes a converters power socket fitted by Fiat , with ignition feed supply etc , these are found at the bottom of the right hand front door B pillar on vans but if you have one fitted could it be around the front seat area ? (right hand side) 

I think that is the item called the 'AD 01' being referred to above.

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No; The AD01 is an additional Schaudt vehicle interface box which is used to control such things as items which should only work with ignition on, items that should only work with a D+ signal present, and items (position lights) which should work with the lights on (amongst other functions).

It has its own 12V supply from the vehicle battery, and provides supply and switching for the above via sensing of the relevant signals. (though it is usual for the D+ signal, for example, to be sensed from the convertors interface in the B-pillar, use of which always requires additional switching capability such as the AD01). 

 

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The converters socket, if fitted (and it is likely) can provide D+, ignition on, and lights on signals if required. All of these are (very) low current signals, which must be used to drive relays to provide the required greater power to any items being driven. The AD01 provides these relays and switching. It needs a high-power 12V feed to provide current to the switched outputs (up to 45 amps total) and, AFAIK it is common practice to take this from the vehicle battery via an externally fused feed.

I still think it is worthwhile checking the function of any marker lights, though in addition to the possible lack of the high power feed, if they (and the mirrors and split charge) aren't working, it is obviously possible that the 15-way converters socket connection has "backed off". 

If the AD01 is reasonably accessible, then it should be easy to check the high-current input at the box.

 

...and, just to clarify, the function provided by the AD01 for the D+ signal is simply an "amplification". It is protected by a polyfuse (self-resettable) limited to 2A output - the EBL uses this amplified D+ signal to drive further relays for higher power use (eg split-charging). The other conventionally-fused outputs are for rather higher, direct use.

 

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Thanks guys for all this.

There is a converters socket and power wires x2 and 4 1.5mm wires run from it to the AD01.

The power feed to the AD01 is good.

On ignition on 12v should appear on Pin 2 of the AD01. It doesn't!

The D+ goes to 0v on engine running and a relay 'inverts' it to 12v to drive via the poly fuse ths split charging etc.

So why am I not receiving an ignition on voltage from the Ducato via the converters socket on the AD01???

 

Puzzled

Ian

 

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The ignition-on signal from the converters socket is (at least on later versions than yours) also protected by a fuse in the dashboard fusebox. As described for the X290 it is F49. 

I would expect similar protection for earlier models, but fusebox layout might vary.

F49 (X290) is described as covering "Parking sensor control unit, radio, steering wheel controls, central control panel, left control panel, auxiliary panel, battery disconnecting control unit (+key), Trailer
hook, Rain sensor, Current stabiliser (for S&S)" - you might search for similar for your year (or check all the fuses in that box).

I'm rather confused that you imply that the D+ signal out is working, but that you're not getting leisure battery charge? That signal should be transferred to the EBL to work the split-charge relay in there. I'm not aware of the ignition-on signal playing in the split-charge space, but if you are having issues with charging, it might be useful to post the EBL model number.  

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5 hours ago, ian81 said:

 

Cant see any evidence of chafing. Starter battery is charging properly -no red light- and 14.2 on the lighter socket. Thanks for your help.

Its not easily seen its would be almost down where the support bracket leaves the inner wing and comes up to  the ECU I think you'd need to remove the plastic box above it to see it. I  stripped the loom from alternator to the ECU following the wire before I found the worn wire I should have started the ECU end

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30 minutes ago, Robinhood said:

I'm rather confused that you imply that the D+ signal out is working, but that you're not getting leisure battery charge? That signal should be transferred to the EBL to work the split-charge relay in there. 

That's what I had when the D+ signal leaves the alternator it goes to the ECU the engine battery continued getting charge in my case the ign lite was on. Fault happened in Portugal and I spent a month there then drove home No charge to leisure battery's, auto retract on Step or Fridge didn't work  on electric. 

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You have got to take the N/S headlight out to see where the wiring loom chafes on a 2008 era Ducato.  Surprisingly, the loom insulation can actually chafe through on the smooth round metal tube that supports the ECU.  Because the loom rubs the paint off the tube so it rusts, making it like sandpaper where it touches the loom, and smooth everywhere else.  You need to pull the loom away from the tube to see it.  These are photos I took of mine.  I taped up the loom and part of the tube with red insulation tape, then covered both with rubber hose for good measure to stop it chafing. 

Even if this isn't the cause of the fault its worth having a look and taping it up to prevent further problems.302793181_X250ECUloomunderNSheadlight(1).thumb.jpg.532315965b51773525172b9caf0648b0.jpg539201843_X250ECUloomunderNSheadlight(2).thumb.jpg.932736b8592390eeddf5f09079a101a8.jpg1276479335_X250ECUloomunderNSheadlight(3).thumb.jpg.48704407ab9e9ab4eb98840fa323f5cd.jpg

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1 hour ago, witzend said:

That's what I had when the D+ signal leaves the alternator it goes to the ECU the engine battery continued getting charge in my case the ign lite was on. Fault happened in Portugal and I spent a month there then drove home No charge to leisure battery's, auto retract on Step or Fridge didn't work  on electric. 

..yes, but I interpreted that the OP indicated that the functions driven by D+ at the AD01 are working correctly (i.e. the converters socket connection is dropping to earth, and that is driving the relay in the AD01 to "amplify" the signal, (and it has been measured) which is passed to the EBL to switch the split-charge. 

I may have mis-interpreted this.

It is clear that he has a problem with the ignition-on circuit, but this is not driven from the D+ signal, but rather from an ignition feed in the dashboard fusebox.

 

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Thanks to all for the above contributions.

Especially thanks to 'Robinhood' I checked the internal fusebox and in my case found that F49 a 7.5a fuse had blown. This was probably caused when a previous owner had modified the connections to the iso radio socket badly and this had caused a short.

Once again this forum proves its worth.

Ian 

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