SOLVED: Rear light problem

[Pauly]

Have you cleared all the codes ?
Do they come back ?

 

[Mark72]

Yeah the codes come back

 

[Mark72]

Looks like there's no power going to the rear indicator and side rear light bulbs (top rear light bulb is working) totally miffed

 

[Mark72]

Still have a problem with my rear light & Indicator it's only on the right side rear light where the indicator & rear light has stopped working.

I had a tow bar fitted a few months ago which is the relay type but all the tow bar electrics are working apart from the indicator

I have checked & changed the bulbs but still nothing, The battery has been fully charged as suggested, tried disconnecting the battery to clear codes, checked the under seat wiring I have checked & changed the bulbs but still nothing

I have even tried swapping the rear lights around to check if the rear light unit was faulty

Any suggestions I'm stuck thanks

 

[mmi]

The van is a 2018 12,000 miles so all new, it has been converted into a camper also had a towbar fitted about 6 months ago, everything was ok and it was used daily until the lockdown where its not been used much.

The camper install is really stand alone apart from the Ctek charger linked to the lesuire battery but there is a cut off switch that isolates the two


I just ran Carista through it and this was what came up

Engine 25126 Not sure what this is

ABS 00072 Tracers for fog tail light
00088 Load monitoring for starter battery
04199 Not sure what this is

Central Elec 01758 Bulbs for rear light
03432 Central Circuit parking light Right
03432 Central Circuit parking light Right

Thanks for you're help at my wits end with this

Carista sometimes associates the fault codes strangely. Anyways here's a second opinion - what OBDeleven/VCDS think:
25126 - Databus, error message received (engine)
00072 - Rear fog light button
00088 - Charge monitoring for starter battery
04199 - Telemetry control module, GPS module
01758 - Lamps for brake lights
03432 - Activation of right parking light

Still have a problem with my rear light & Indicator it's only on the right side rear light where the indicator & rear light has stopped working.

I had a tow bar fitted a few months ago which is the relay type but all the tow bar electrics are working apart from the indicator

Do the break lights work, and rear+trailer fog lights?
So rear right parking light works for the trailer - but not for the van? Have you checked the tow bar connections into van's wirings?
Does "the relay type" mean the van doesn't have actual control module for the trailer - "Detailed ECU info" in Carista?

 

[Mark72]

The relay for the towbar in tucked away so have to take the bumper off to check, brake lights are working the indicator and the rear light bulbs at the side (the top rear light is ok). Do you think the tow bar relay would cause the fault ?

 

[mmi]

Difficult to say anything about the relay.

The +12V (flash) to the right rear indicator goes through brown 17-pin connector T17f/pin 12 (under left seat) in black/green wire. Perhaps worth to measure there - however as front indicator and repeater are wired to the same point and as they are working - that won't give new information.

Anyways, there are no other connectors before the rear right cluster - just need to find the disconnect.

 

[Mark72]

Thanks for your help

I'm thinking it must be the tow bar relay as that's the side it's on

 

[catfood12]

Still have a problem with my rear light & Indicator it's only on the right side rear light where the indicator & rear light has stopped working.

I had a tow bar fitted a few months ago which is the relay type but all the tow bar electrics are working apart from the indicator

I have checked & changed the bulbs but still nothing, The battery has been fully charged as suggested, tried disconnecting the battery to clear codes, checked the under seat wiring I have checked & changed the bulbs but still nothing

I have even tried swapping the rear lights around to check if the rear light unit was faulty

Any suggestions I'm stuck thanks

Well that's not right then. Do you have 12v on NS & OS rear lamps on the towbar socket, pins 5 and 7 ? Some trailers lazily take both rears from just one pin, rather than extend both all the way back.

It's sounding like the towing relay may be at fault. If you have relay then I guess it's not the OEM tow electrics. If you stick it in to the Main Stealer to investigate, they may charge (no pun intended) comprehensively to investigate by the book.....

 

[Mark72]

I'm suspecting it is the relay the company that fitted the tow bar said they would check the relay so saves me taking the bumper off.
Definitely would rather not go to VW

 

[Mark72]

Towbar relay checked all ok another scan shows there's no power going to the rear right indicator and rear light, also my brake lights are dim, there's a start/stop error on the dash and after taking the van a few drives it's not doing any regeneration the battery's been recharged using a charger.

Any thoughts

 

[Loz]

If the brake lights are dim, what voltage are you getting at the lamp, across the terminals without the lamp? then what voltage from lamp live to chassis?
Still sounds like an earth fault to me.

 

[Mark72]

No indicator, no part of tail light, dim brake lights, no fog lights, start/stop error and engine not doing any regeneration at 12,000 miles. VW never again Thanks for the help

How would you test the earth at the lamp I know the brown is earth, would you run a cable from the connector or the bulb holder

 

[Mark72]

Just tried earthing the rear light connector and checked the voltage with the lights on but nothing

 

[Loz]

Assuming you have tested every fuse.. (use a continuity tester across the small metal bit through the small holes in the top of the fuse, saves removing them)
Have you tried a BCU reset?
Disconnect battery and touch the cables together to discharge vehicle units then reconnect.

 

[Mark72]

Yeah I've disconnected the battery and touched the cables, I'm going to check the wiring under the passengers seat again, I've got a swivel seat so will have to remove the seat. I've checked all the fuses must be something silly

 

[Spaghetti]

If you’ve got a double swivel, the wires are normally tucked under the rubber floor by the handbrake. Could some of them become damaged or disconnected?

 

[Mark72]

I did check these but I'm going to recheck the connections and the voltage with a multimeter

 

[Mark72]

Anyone know which of these cables run the rear right light thanks

 

[Deaky]

The 17 pin green connector and the brown connector.