Technical Located at the bottom of pillar B, right passage side there is a multi connector.

[Aladdinvej]

This is written via Google translation hope you understand my question.
I have a Fiat Ducato motorhome (Van), year 2019.
Located at the bottom of pillar B, right passage side there is a multi connector.
Pin 2 should be the 12 volts D+ (motor started and generator running) but suddenly this is not working anymore.
Has anyone of you seen the wiring diagram from the connector to the generator and could there be a hidden fuse something?
Hope you understand my question
Otherwise really happy new year
Flemming
Denmark.

 

[HughJampton]

I'm pretty sure that the signal provided on pin 2 here is not 12 volts, but that the pin goes to earth (ground) to simulate a D+ when the alternator is functioning.

This is intended simply to act as a ground signal to an external relay provided by the motorhome manufacturer, switching 12 volts at whatever current is required in an external circuit.

It would explain why there is no voltage at the pin with the engine running (if you have a multimeter, you can test for continuity to ground with the engine running).

I've seen it fully documented somewhere, but I can't find it (though the "Converter's manual" does describe it as "D+ (active at ground)")

 

[Reg 65]

The Converter's Socket is an optional extra costing about £60 + VAT.
But some recent Ducatos like mine have one fitted, even though it is not on the spec sheet or been charged for.
This is the best guide I have found

Converter's socket - MisterG

The Peugeot Boxer, Citroen Relay and Fiat Ducato can be equipped with an option for a “Conversion Interface” or Converter’s socket. Fiat: “Electrical Interface Supply Socket (For Conversions)” option 081 Peugeot: “Electrical connections interface box / Includes reinforced alternator” option JI01...

misterg.org.uk

Even so, you can't rely on it because FIAT have an annoying habit of changing the wiring colours.
I think they must have run out of some colours and used whatever colour wire they had to hand.

 

[HughJampton]

The above confirms that Pin2 goes to ground when the alternator is running (and describes the indirect method how this is used to provide a 12V signal if required).

===

D+ / Charging Signal​

The D+ (‘Charging’) signal is not as straightforward: Pin 2 of the connector actually goes to ground when the alternator is charging, rather than to 12V like a true D+ signal.

In order to generate a true D+ signal it is necessary to wire a relay into the circuit: Relay pin 86 should be connected to pin 13 of the converter’s socket (+12V supply with limited current – suitable for 2 relays / 600mA max). Relay pin 85 should go to pin 2 of the converter’s socket (active low D+ signal). It is a sensible precaution to use a relay with a built in protection diode to reduce the risk of damage to the ECU.

The fuse is just sized to protect the D+ wiring and supply any loads on the D+ circuit.

The 12V for the D+ signal could come from pin 13 of the converter’s socket too (connect relay pins 30 and 86) if the loads are very low, and you are confident that the total load on pin 13 won’t exceed Fiat’s 600mA limit.

===

My own motorhome uses a Schaudt ADO1 unit to convert to output a number of 12V signals on D+, and from the circuit diagram you can see that the D+ signal it uses is in fact the ground from the converters socket Pin2 - used to operate a relay and provide 12V from a separate supply.

 

[Aladdinvej]

Hi

First happy new year.

Thank you for your answer, now I have something to work on ..
Many greetings

Flemming
Denmark