Tail light change

[Sunny43.5]

Hi all we had a tiny boo boo the other week and ended up breaking one of the tail lights on our 2012 T5.1 Transporter , so rather than just putting standard ones back I ordered some very trick LED style ones . They are the ones where the indicator flashes from one side to other , any way when plugged in the indicator at the front flashes normally but the dashboard light flashes rapidly and the new ones at the rear don't work at all . Also same for the brake and park lights nothing works , any ideas on a work around or other ideas {yes I have contacted the seller but no response yet .}

[DV52]

@Sunny43.5: Hi.

I'm not familiar with the tail-light wiring on a Transporter - but this retrofit has been done many times on other VAG vehicles. The fundamental issue when fitting LED tail-lights to a car that was factory built with incandescent lamps in the tail-lights is the number of separate lamps in the two installations.

Again, I'm not sure about a transporter - but in general, VAG cars with factory built incandescent tail-lights have LESS lamps. This normally means that the wire-count in wiring loom from the module that controls the tail-lights to the rear of the car is LESS than in cars that are factory built with LED tail-lights.

Because there is insufficient separate wires to supply power to the extra LED lamps in these situations, normally a "cross-wiring harness" is installed between the factory tail-light connectors and the new tail-lights. This harness works by joining together lamps in the tail-lights that have the same lighting function thereby resulting in a spare wire that can then be used to supply an extra LED lamp.

For example: on factory wired tail-lights, the cable loom that terminates on the tail-light connectors has separate wires for the Brake-lights on the left/right car-side. The cross-wiring harness joins together both Brake lights onto one of these wires and in doing so creates a spare wire. This also happens to the Parking-light lamps on the left/right car-side.

Hope this makes sense!!

Anyhow, the key consequence of the cross-wiring harness is to re-allocate the factory wires to different lamps on the tail-light fittings. This means that the module that controls the tail-light lamps must be re-coded to align with the new set-up

Finally, the arrangement that I describe above is most-definitely non-OEM - this means that each non-OEM manufacturer of these tail-lights has their-own design and their-own set of coding changes!!

Don

[Sunny43.5]

Thank you for the response I have had some thoughts on how to bypass the issue as I did the same thing with our towbar / trailer lighting many years ago . We sold our old 2005 T5 which was fitted with a towbar from Hayman Reese by the dealer , I removed the harness and tow bar and refitted it to the current one and bingo the lights all went beserk ! I was contemplating using a series of relays which would "hide " the trailer LEDS from the vans system , but one day while driving past a tow bar shop here in Brisbane I stopped and asked the guys there if they knew of a solution . The guy whipped out this little black box with lots of wires and said this will do the job . It turned out to be a specific part made for this model VW by Hayman Reece , and you guessed it inside was series of relays so all I had to do was tap into the original wires near the tail lights and run the trailer lights from the little black box . That was 12 years ago and it still works perfectly with those LED trailer lights , so once I hear back from the supplier that will be my next option some relays to again "hide" those leds from the VW system .

[LogicprObe]

I was surprised when I got sick of changing the bulbs in the daylight running lights and got a couple of cob leds from China.
Worked no problems and still going over ten years later!

[Sunny43.5]

Received a conversion kit from the suppliers, the tail lights are now working and look great .