Ducato 2018 L2H2 Thule V16 electric step wiring. | MotorhomeFun | The Motorhome Support and Social Network

Ducato 2018 L2H2 Thule V16 electric step wiring.

Sep 13, 2018
Funster No
Fiat Ducato MH2
Since 2000
I've fitted the electric step no real problems. It works a treat!
I've also put in the optional relay & capacitor which retracts the step automatically when you turn on the ignition.
Now I have a niggling concern permanently connecting this 'trigger' wire.
The latest (I know of?) Fiat Ducato convertors and upfitters manual called ** "New Fiat Ducato 2016 Converters and upfitters manual" **
Shows the B pillar converters socket but the wire colours are mostly different and go to different pins to the ones on my 2018 vehicle.
I found a blue/yellow wire going to pin 5 which goes 12v live when the ignition key is turned.
Fuse 49 in the dashboard fusebox when removed disconnects this wire.
I believe this is the +KEY wire which I believe is the one I need to connect to to activate the relay which auto retracts the step.
It works but I'd really appreciate if there is anyone who knows better.


Free Member
Dec 8, 2017
N Wales
Funster No
Self build PVC
Hi - surprised you haven't had an answer to this yet:

I found that in my 2018 X290 Citroen Relay the wiring colours on the 15 way socket matched the colour codes (and wiring sizes) in the older Fiat Converter's manual, but not in the positions indicated. I didn't have the new converter's manual at the time, but the tables look very similar. This is the old one:

15 way functions.jpg

Italian colours:
15 way colours.jpg

Numbering from the converter's manual:
15way wrong.jpg

When I worked it out, it seems that this is the numbering that they've used:

15 way.jpg

The colour codes, wiring sizes and the few functions I could check all match this numbering.

Note that this is the view looking at the side where the cables emerge on the van side of the connector (i.e. the side you can't see!).

What you think is pin 5 becomes pin 13 on this numbering - i.e. Key+

I took the switched 12V signal for my B2B charger as shown below:


Hope this helps :)
Last edited:
Sep 13, 2018
Funster No
Fiat Ducato MH2
Since 2000
Yes that is very clear and has solved this problem.
I thought the diagram was wrong and unlike yourself tried to transpose the pinouts.
I thought I'd tried every permitation and got more and more confused.
The Italian abbreviations for the wire colours didn't help.
My sketches had so many crossings out I gave up and asked.
Thank you again.

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