2011 Citroen Dispatch 2.0D Hazard, Trailer Lights and Heater not working

farmer2018

Hi all, the hazard lights and trailer socket lights have stopped working in my 2011 Citroen Dispatch 2.0D. Would the causes of these not working be blown fuses or what? The heater is also only blowing on heat setting 4. Opinions welcome please.

zg3409

It could be fuses. A bad trailer could have shorted out wiring and blown fuses. Sometimes the wiring on the car side can be damaged or pulled too.

farmer2018

I checked van trailer socket with a multimeter and there is power getting to the socket but the trailer lights still won't work, would it be a problem with the relay? I checked the trailer lights with another vehicle and they worked perfect.

Irish Steve

If the hitch and wiring were an after sale addition, there is a possibility that the relay power has been taken from a different fuse than you may be expecting, and in some cases, the fuse is not even in the fuse board area, and it may be getting supply from a completely different system, with an additional in line fuse then fitted to protect just that device in close proximity to the relay device.

I had a similar example a few months ago where the fitter had taken a supply from the rear seat 12 V supply to the cigarette lighter socket, and then fitted the relay fusebehind the rear quarter panel trim panel, so it took some searching to find it. Another recent fitting, the relay, and an associated fuse were behind a trim panel on the rear of the passenger door, so another pain to find and fix.

farmer2018

https://www.boards.ie/discussion/comment/118843470#Comment_118843470

Thanks. It's fitted with a bypass relay at the rear light

Irish Steve

And that relay has to be getting a power supply from somewhere, and there won't be a dedicated 12V live supply at a rear light, so whoever fitted it took a supply from something like the interior light supply, and may have put a separate fuse in the line between the light and the relay. It might have a supply line back to the fuse board, but that might not be the standard.

farmer2018

https://www.boards.ie/discussion/comment/118843644#Comment_118843644

Yes but the strange thing is there is current on all wires coming out of the relay to the light socket for the trailer. Current at the trailer socket too for all pins.

They are taking power off a cigarette lighter below the back of the opposite rear light

Irish Steve

OK, in that case, check that the earth to the socket is good from the pin in the socket to the bodywork, if that's gone high resistance or open circuit, nothing will work.