Fiat Ducato fault on rear light

[DaveWilly]

We have a Timberland Destiny Motorhome, based on a Fiat Ducato 120 Multijet. We bought it new in July 2008. Back in January 2014 we had a problem where the rear offside red light (Side/Brake light) was flickering / staying on, when parked on our drive. We had a local garage investigate and couldn't find the fault. We then took it to Fiat Stoneacre at Wrexham (17th Jan 2014) and they couldn't find the cause, even though their diagnostics system brought up a fault code. The fault never happened again - till a couple of weeks ago (Oct 2014). The light goes out when we open any door.

An auto-electician did a diagnostics check, which reported some errors, but no clue how to fix the problem.

The faulty light drains the vehicle battery overnight to a level where I cannot start the vehicle and need a jump start.

I've checked connections in the light cluster.

 

Has anyone else had this problem?

[lennyhb]

Hi Dave and welcome.

 

My last van was a 2008 X250 I had an intermittent fault on the stop lights and after a few months the stop lights came on permanently (with ignition on ) also cruise control turned it's self off turned out to be an intermittent wire on another circuit upsetting the canbus system. Cost about 400 quid in labour to find the fault, it was only a few months old so under warranty, the convertor had nicked a wiring loom under the seat when fitting the leisure battery.

 

Although may not be not relevant but shows that a fault somewhere else on the system can cause what appears to be an unrelated problem, I think you will have to try and find an auto electrician who is used to working on Fiat canbuss systems.

 

Nick (euroserv) may be able to put you in touch with someone or may even know a solution.

[flicka]

My guess - for what it's worth -- Is a trapped wire, possibly in the link between the main body & rear door, were the insulation has been cut or the conductor wires have frayed. A multimeter check should confirm if wiring is carrying full current. Try moving the door (closed to fully open) whilst the multimeter is connected to see if there is any current variation.

[DaveWilly]

Many thanks for your replies, Lenny and Flicka.

It's like looking for a needle in a haystack, looking for a fault in wiring.

I did a test last night, checking the battery status. In 6 hours, the Vehicle battery dropped from 12.5v to 11.8v, the in the next 6 hours it dropped down to 4.9v, which is horrendous. I couldn't turn off the alarm as there wasn't enough power, and had to turn off the central locking by key. Then I connected the hook-up cable, and was able to turn the alarm off.

So something is draining the battery badly - something more than a faulty rear light, methinks.

 

Yes I think I'll be contacting an auto-electrician. I know one in the Liverpool area, who ran a diagnostics check a few weeks ago, and "thinks" the fault may be in the main vehicle Marelli component (approx £200 to send away for repair he reckons). But he didn't sounds too sure. But I may have to bite the bullet and go down that route.

 

regards

Dave

[Brian Kirby]

Have a look at this string, particularly the post by euroserv: http://tinyurl.com/mulxab8

 

There appears to be a nest of cables (and the plug referred to) behind the l/h headlamp unit that is particularly prone to failure through chafing and eventual shorting between cables. It has been mentioned several times before.

 

Use the search facility and enter euroserv as author and cables as subject, and set time to all posts. You'll have to sift through several responses, but there is one where he gives fairly detailed instructions on what to look for, where, and I think there may be some pictures as well.

 

I seem to remember his warning that the search is time consuming and would prove expensive if paying an auto electrician to do the spade work.

 

The symptom you describe sounds to me as though it relates to current getting onto wires it is not supposed to reach with the ignition off, which suggests contact between various wires in close proximity, hence I thought of that apparently notorious bundle. Hope this is not a red herring, and good luck!

[DaveWilly]

Thanks for your comments, Brian. I think I found the thread you referred to (water leaks into ECU), though I couldn't see any pictures. I think it's beyond my skills, and I've been in touch with Timberland, who did the habitation conversion, and am awaiting for their judgement on whether they can take on the job during my next vehicle service. I suspect they will suggest going back to Fiat or my auto-electrician (I favour the latter really).

Whatever happens, I will show them the details of the thread you mentioned.

 

Thanks for your time.

Dave

[Billggski]

I've only done this kind of work on a Saab, but a check of any wiring that is visible could save a lot of money. Not just a visual check but separating bundles to see if anything is chaffing. Usually around moving parts like doors, which sounds like your problem. On the Saab it was the boot lid, a search brought this up as a likely place, so I followed the cable along. The "canbus" system means the fault can show up in unexpected places.