I connected pins 7&8 as advised, and boom!
I was able to scan lots of modules.
I found out why the trunk lid was popping when I turned off my lights.
At first i got a trunk latch from the scrap yard, but after replacing it the problem remained.
I took apart the piece with the trunk button and everything was corroded. This explains how the trunk lid was shorting with the licence plate lights.
The OBDII port seems to be doing fine.
I cleared all the errors in all the modules and will rescan tomorrow.
Unfortunately I was unable to get the MAF sensor as the only X5 at that scrap yard was 4.4L
I'll try again tomorrow with another yard.
I have to restart my car way more often now, maybe 10-15 times on my way to work, which is only 5 km.
I'm thinking it's because of the MAF sensor. I tried disconnecting it altogether but things didn't improve.