Technical Rear light fault

[DaveWilly]

We have a Timberland Destiny Motorhome, based on a Fiat Ducato 120 Multijet. Back in January we had a problem where the rear offside red 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.

Has anyone else had this problem?

 

[gareth111278]

A few questions.
1. Is the fault only there during / after wet weather?
2. You say rear red light, I assume you mean the tail light not brake or fog lamp?
3. Do the side / tail lights either flash when you use the central locking or come on for a few seconds when you un-lock?
Cheers
Gareth

 

[DaveWilly]

A few questions.
1. Is the fault only there during / after wet weather?
2. You say rear red light, I assume you mean the tail light not brake or fog lamp?
3. Do the side / tail lights either flash when you use the central locking or come on for a few seconds when you un-lock?
Cheers
Gareth

Gareth, thanks for your reply. Here are answers to your questions...

1. The fault appears during any weather.
2. Our vehicle has 3 lights in the rear cluster - tail side light / brake light, Indicator, fog lamp. It's the top one (tail side / brake) that is the problem.
3. The side / tail lights do not flash when I use the central locking nor do they come on for a few seconds when I un-lock. The indicator lights do so.
Cheers
Dave

 

[gareth111278]

In that case I'm stumped!
I thought it might be wet in something like the unit that puts the lights on when you unlock.
As its just one lamp its tricky.... If it was all of them I'd say its the circuit either picking up an earth or a live depending if its positive or negative switched.
First I'd try checking the wiring to the tail lamp cluster in question for visible defects. Does it have a tow bar? Shoddy wiring connections can cause faults on the vehicle as well as the tow socket.
Where in the country are you?

 

[gareth111278]

Sorry , just seen you are Wrexham area.
Its not the side with the reverse light is it?

 

[DaveWilly]

Hi Gareth.
It's got everyone stumped. We've checked wiring and other places for corrosion etc, including the 2 marker lights at the top of the vehicle.
We don't have a tow bar.
We live in Liverpool. I took it to Wrexham, as the Fiat dealer in Liverpool can't examine Motorhomes as they have a height restriction.
Both sides of the vehicle have a reversing light in the cluster.

The Auto-electrician who came to our house to run diagnostics was flumoxed. He ran a diagnostics check on the main ECU and believes it is a fault in the ECU itself. He quoted approx £200 to take it out and send it for repair and further tests. I may leave it till after Christmas to do this.
In the meantime I phoned another Fiat dealer, and they said they would have to start with another dignostics check for another £90!
This is why I posted my question on this forum, in case someone else has had a similar problem, and had a solution.
Thanks for your interest.
Dave

 

[The Seasider]

Dave you dont say how old your motorhome is .. but heres a theory to throw into the mix ..............................

On "newer" vans & cars they have Parking lights .. these activate if you leave your indicator stalk "ON" after removing the ignition key .. i.e if you left your stalk with your right indicator "Flashing" & removed the key the "Parking Light" would illuminate on the Right side & the same if you left the stalk in the Left position....... the Left parking light would illuminate ect ....

"Paking Lights" use the Rear side light & the front side light on each side (Depending of course which way you leave the Stalk in the cab)................

I would be looking down THAT route if I were you ... for a loose connection within the Indicator stalk ...Hope this helps

Keith

 

[DaveWilly]

Dave you dont say how old your motorhome is .. but heres a theory to throw into the mix ..............................

On "newer" vans & cars they have Parking lights .. these activate if you leave your indicator stalk "ON" after removing the ignition key .. i.e if you left your stalk with your right indicator "Flashing" & removed the key the "Parking Light" would illuminate on the Right side & the same if you left the stalk in the Left position....... the Left parking light would illuminate ect ....

"Paking Lights" use the Rear side light & the front side light on each side (Depending of course which way you leave the Stalk in the cab)................

I would be looking down THAT route if I were you ... for a loose connection within the Indicator stalk ...Hope this helps

Keith

Hi Keith, thanks for your suggestion.
Our vehicle is June 2008.
There are no "Parking lights" on this version. I did think about this as a possible cause some months ago.
I think I'll have to leave the problem till after Christmas, and stick with the Auto-Electrician getting the main ECU checked out.
regards
Dave

 

[DaveWilly]

Just thought I'd give a quick update......
On Monday afternoon I found that my Vehicle Battery had dropped to 2.5volts, so I couldn't turn off the alarm. I immediately put the vehicle on Hook-up.
Today at 8.30am I bit the bullet and took my motorhome back to FIAT Stoneacre at Wrexham. After about 5 hours they were unable to find the cause of the fault - the brake light still lit up with no ignition on.
I came back to Liverpool on the train, leaving my motorhome with them.
Like the auto-electrician who came to our house, they suspect the Vehicle Management Controller, but it costs approx £750 (incl VAT). Tomorrow they are going to do a bit more research, probably detatching some of the 3rd party wiring, before seeking my agreement to order a new unit.

 

[adlarplant]

Long shot here i know but Ive seen cases of bad earths in vehicles causing lights to come on before is something still running after the vehicle is switched off and earthing out through the light itself ? Cheers adam