Dipped headlights not working

[Powerful Pierre]

I have a 2010 Adria compact with on a Ducato 130 multijet On coming home the other evening I discovered that the dipped beam wasn't working although side lights and main beam were fine.
When you switch dipped beam on they come on for a split second and then nothing so the bulbs must be OK I have fiddled with the switch but to no avail
I was wondering if all this torrential rain could be the cause but where?
Has anybody else had this problem?

 

[Landy Andy]

If you have a short in the circuit on any part, the ECU will cut the power after it discovers the issue. This will then do exactly what you have. Brief lights on then system off. I‘d suggest you could have something as simple a a failed bulb but where the inner element is shorting. This will cause the power to be removed. Water into a connection, is also an option but starting with the basics first would be my plan.

 

[Powerful Pierre]

If you have a short in the circuit on any part, the ECU will cut the power after it discovers the issue. This will then do exactly what you have. Brief lights on then system off. I‘d suggest you could have something as simple a a failed bulb but where the inner element is shorting. This will cause the power to be removed. Water into a connection, is also an option but starting with the basics first would be my plan.

Thanks will wait for a bit of dry weather then start checking

 

[GeoffnDee]

Powerful Pierre , If dampness or faulty bulb is not found to be the problem ,There is a relay ( T01 ) linked to low beam operation in the dash fuse box , . The relay and wiring can be seen in the Fiat Ducato X250 power supply and headlight wiring diagrams that are on page 4 of the Motorhome technical articles section , in Resources ( Found at the bottom of this page )