08' MK5 Gti Tail light problems ( not fuses or bulbs )

[justinh510]

Hello, I have a 2008 GTI 2 door, about a year or two ago,
i had an electrical problem ( my fault i wired something up wrong )
It melted the body control module under the driver side dash causing everything electrical to go crazy.

(

)

I ordered a used BCM from a mk5 jetta online to replace it. however one of the connectors to the BCM melted as well, so i went to the junk yard and got one off a jetta of the same year to just splice to the existing wires. everything matched exept a yellow and white striped wire. there wasnt a wire coming from the junk yard connector. however everything started and ran perfectly fine.



its been so long so i don't remember 100% but i think the tail lights worked too.
it wasn't until i got pulled over for driving at night with no tail lights at all.

the brake lights, turn signals, reverse and hazard lights all still work as they should.
when i pulled the headlight switch i saw a small yellow and white striped wire.

everything in the back is grounded well and the connectors are clean.
ive checked almost every fuse in the car and they all look fine ( can't find a accurate fuse diagram online to know exactly what fuse to look for )

I feel it could be either something with the programing with the BCM, or possible the yellow and white wire that is just hanging there connected to nothing.
does anyone have any ideas or know what direction i should head in?
I was not in the position to really mess with it much
so i've been just driving during the day

I have Pictures after i post this ill get them on the pc and upload them.

thank you

 

[justinh510]

here is a bunch of pictures of my situation currently
including the ( temp splices )
yellow and white wire.
the connector from the junk yard
and the yellow and white wire in the headlight switch

 

[justinh510]

any ideas?

 

[GTI's]

Yellow/white at light switch is for fog lights if equipped with them and seeing this is a GTI it should. It is on PIN 5 of that connector plug and goes to J519 connector plug E PIN 6

Did you recode the replacement module with your old coding? Do a scan with Vcds or equivalent for current dtc??

PS seeing that your brake lights & turns work the wiring is fine from J519 to the tail lights, tails function when about 3v is sent down the wires to both of the blubs in the tail light housing.

 

[SparkySDI]

Can the individual relays be changed without swapping the entire unit? If so, how do I identify which one is designated for the left rear tail lamp? I ask because I have intermittent issues with a "failed" lamp. Bulb is not blown and all local connections are sound. Problem comes and goes. Sometimes within days, other times within minutes. I feel as if this is a good place to try another approach.