Tail light issue on 06 530xi wagon
 

So I have been trying to sort this out for months but all the info I find is either outdated or relates to sedans.

Im getting idrive warnings for both of my tail lights, license plate lights and my reverse lights.

Symptoms
1 - Both the running light and brake light (both lower bulbs) are always illuminated when the lights are active on the left drivers side. They both get brighter when the brake is applied.

2 - Only the running light (bottom outside) bulb is active on the right passenger tail when stationary but both the running light and brake light come on when the brake is applied.

3 - reverse lights and license plate lights do not work. (Assuming this is the hatch wiring)

Here is what I have done so far...
1 - checked the wiring harness to both tails. I saw no damaged wiring.

2 - checked the connector that plugs into the tails. I saw no damage.

3 - checked the actual tail light. One bulb socket had began to melt on the left drivers side tail (the lower outside bulb)

I ordered a replacement drivers side light and the error for that light is now gone but both lower bulbs are still Illuminating when the lights are on. The warning for the right passenger light is still active.

I really dont want to fry another light. Please help...
(I will update this post with pictures asap.)

Ok so I just removed the passenger right tail light and saw that there was indeed corrosion on the inner bulb holder.The plastic around where it seats on the taillight side had also started to melt.

I cleaned up the connection the best that I could and was able to get both tails to function properly but I still have no idea why this is happening.

As far as the hatch wiring goes where can you purchase the replacement/repair kit? My local dealer wanted 1300 for a replacement harness.

Is it normal for both of the lower bulbs to be illuminated when just the running lights are on? Seems odd for a single filament bulb.

Nobody?