Technical 1992 Dethleff rear lights not working

[Robdangereux]

Hi all, a newbie here. I was looking for an answer to a puzzle on my 1992 2.5td fiat Ducati Dethleff motorhome and came across this site so joined and thought I would ask. I usually work on my van Myself but this has got me puzzled. The rear lights red, not brake lights, don't work. They were one moment then weren't the next. The side, head main/dip all work, all fuses I can find ok and my back up camera which is wired on lighting circuit works. The indicators, reverse lights and fog lights all work front and rear. What has stopped working is the rear red lights and the dashboard lights on, indicator bulb. I can here the relays clicking in but due to everything being built in can't find the problem especially considering the wiring runs both sides of the van. Long post but any ideas? Cheers

 

[cid]

Hi, Have you checked power by removing lights and testing? If there is power it is, most probably, a bad earth going on age of van. All the Best, Ian. P.S. Please let us know either way.

 

[Communicator]

I cannot accept the logic of a "bad eartth" as the fault affects both sides on the vehicle, which are described as being separately wired, and the other lights at the rear are not affected.
As a motorhome is a conversion of a base vehicle, all wiring to the rear of the cab area being supplied by the converter, Dethleff in this instance.
I would expect to find a junction box(es) where the Dethleffs wiring connects to the original Fiat installation. A fault in this junction box may explain the problem at the rear, but not the dashboard. I have a memory of reading about a similar fault, where there was no junction box, and poorly executed connections had been pushed into a hole in the chassis. I would not expect to find a relay in a basic side/tail light circuit, but it could be for side marker lights, again part of the Dethleffs conversion.

Given the age of the vehicle, I suspect that it is based on a first generation Ducato, but it could be an early x230. if @Robdangereux can confirm the first three numbers of the VIN, then tis can be resolved.

 

[cid]

Hi again, Correct me if I'm wrong but, is the base vehicle not supplied with working rear lights, indicators etc. and does the converter not take their supply from these if they want to relocate the lights. That seems the logical way of doing it rather than chopping the wiring loom off and starting from scratch. Ian.

 

[Robdangereux]

Hi everybody thank you so much for your replies. To answer some questions: The lights are removed as I was about to replace them. I have no power to the junction box either side where I believe the conversion plumbs into the original. All was working albeit partially until the dashboard light for lights on, went out. I swapped for known working bulbs and they do not light either. Relays click, fuses good but no wiring diagram so cannot begin to see what could connect dashboard light with only rear lights. Vin number starts with: ZFA290 Thanks all

 

[Communicator]

Hi everybody thank you so much for your replies. To answer some questions: The lights are removed as I was about to replace them. I have no power to the junction box either side where I believe the conversion plumbs into the original. All was working albeit partially until the dashboard light for lights on, went out. I swapped for known working bulbs and they do not light either. Relays click, fuses good but no wiring diagram so cannot begin to see what could connect dashboard light with only rear lights. Vin number starts with: ZFA290 Thanks all

Unfortunately the 290 confirms a First Generatio Ducato. The Citroen C25, Peugeot J5, and Talbot Express were similar vehicles.
I have a diagram applicable to the immediately following (1993) x230 model, and I will attach, as it could save as a basis. This diagram is an extract from the German language version of the x230 workshop manual, that is available in the downloads section. (See black banner at top of page.)