New to me 2000 E53 3.0i

[Don't shoot me!!!]

Hello boys and girls.
(Sorry for my bad grammar, but hey, you guys probably can't speak Norwegian ;-) )
I have a couple of issues i need to sort out, i'll be back on those issues later in the post.
First, a short history of the vehicle, at least what i've figured out so far...
This particular one has 300.000 Km/186.000 Miles.

These cars had a pricetag of whopping $115.000 in Norway while new.
So when i found one in a bancrupsy auction, i gambled with kinda high mileage and relativily old (Paid $5.500 Thrust me, this is cheap)
I figured that i could spend $4.000, and still have a cheap X5 :-)

I do most of the maintendance on my vehicles my self as i'm to cheap to pay dealers more than i have to, however, i'm not a bloody electritian....

Picked up the car last week, as what i can see from the papers, this was a import back in 2003, sports package, but strange enough without a sunroof..?
Looks like she's been well tended to in her lifespan untill the last owner (Registered on the last owner in Oktober 2015, picked up by the auction house January 2016)

The battery was dead, so i had to mount a new one.
The engine lamp, traction, abs and brakes was on, found that the airfilter box was broken, temporary fix with tape and reset the codes, problem solved.
The triangle of brake lights should be easy enough as the speedo doesn't work, picking up a abs sensor for the rear left side tomorow.

On the way home i noticed that the engine were to cold according to the gauge, but still get to opperating temp on idle.
Again probably a easy fix, new thermostat arrives tomorow.
I had one faultcode on the way home that i just reset, don't remember the code, but i think it was something like "Bank 1 running to lean"
My guess is the air box combined with the thermostat?
Haven't showed up after the reset.

Still, engine runs smooth, no strange sounds, no leaks, trans seems fine, oil looks and smells fine, suspension, bearings, callipters fine...
The hood have some minor rust spots, the back lid.... WTF???
Need to source both top and bottom lid due to rust.

Parking sensors front and back doesn't work, and the PDC button blinks.
Haven't looked into that yet, but i do asume that the system fails if one sensor is bad..?
Does that aply for all eight sensors, or is the front and rear two different systems?

The ballast on the left side was faulty, and i'm quite shure that's why the airfilter box was broken....
For me it looks like that the previous ovner blamed the air box with his fist when he figured out that the ballast went bad...?

¤%"¤%/# i guess bloody morons are born every minut :-(

Fixed that with a cheepo xenon kit i allready had in my garage.

It allso looks like the previous owner had a different satnav, and he probably removed this unit, but forgot to mount all of the OEM package?
All i have is the old 4:3 unit and a broken NAV unit in the trunk.
The cd changer is no where to be found?
Allso, the 4:3 unit have some bad buttons, so i'll ditch that system and go for a Xtron unit like this..

7" BMW 5 Ser E39 X5 E53 M5 Navigation Autoradio Android 4.4.4 DVB-T WIFI RDS OBD | eBay

Yes i know that Dynavin probably are better, but as said, i'm a cheap....

So for the two weird things i haven't figured out..?

As said, had to change the battery.
As a result i had to reprogram/pair the keys.

Keys work in the lock, open the buttons on all the doors exept right backdoor.
The open/lock nois is there, but the button doesn't pop up.
The key in the lock locks all four doors with all four buttons going down.
The sentral lock button on the consol is the same, up and down for all three doors, and the same problem with the right backdoor.

Programed the keys, locks all four doors, but doesn't unpop the drivers door or the right back.
But heres the fun part, after i unlock the doors with the remote, i can't open the drivers door with the key in the lock..?

The second strange thing is, if i park the car without locking the doors, the roof lights come on by them self after an hour or two..?
Not a problem if i lock the doors..? (Yet)

I'm thinking some sort of BCM module?
But does the X5 have one unit for all, or is it several modules all over the vehicle?

I really don't want to buy modules before i'm shure, and my OBD2 can't read these kind of faults.

Still, untill now i haven't needed to spend a great deal of money.
This is a superb car that i will keep for a while, i really love the X5.

(And i was actually considering a Jeep Grand Cherokee from 2001) Hah :-)

Regards from Norway, the place the Trolls run away from because it's to cold :-(