Hi do you just love your E61, I have a 2007 530d and have a similar problem to others with the tail gate wires. I have not got rear screen heater, wiper and the glass won't open.
I can't get to the loom until I open the glass - is there a manual way to open this please, if you have photos I would be very thankful

 

Hi I had the same problem (electric systems in the rear broke down one by one until I actually couldn't lock the doors anymore with my remote)
Basically the entire wiring cable had to be replaced. Cost at BMW dealer was around EUR 1200. This meant replacing the entire cable in the roof from the front to the end. However I had it done at a local BMW specialist who simple replaced part of the cable (access from the rear). He did this by dismantling the overhead interior roof cover at the rear. Cost EUR 400,-. I'm not technical enough so it was worth the money. So good luck.

 

Also there is a PDF link with photo's on how to do it a couple of threads down in this forum:

https://5series.net/forums/topic/727.../page__st__120

 

Hi Bertolli, thank you very much for your reply very helpful. I am going at BMW UK at the moment to fix this at no cost, these parts are not fit for purpose on a car of this quality, maybe the forum shoul have a go at them as well