Many electrical faults happening since airbag light appeared

[Patbol]

Hey guys

I have a 2001 e53 x5 4.4 and I'm having a sudden list of electrical problems with it ever since I noticed out of the blue one day the airbag light came on

I've read the battery can cause electrical faults if it is slightly out with its voltages or its not performing properly but had it tested and was all fine apparently
Car is also throwing no fault codes

Problems I have currently is

Airbag light
Sunviser mirrior turns on the whole cars lights instead of the one above the mirrior
Aircon will turn on and work but the fan won't
Cruise control wont turn on
The multi display in the middle is blank and completely off most times, sometimes running fine other days
Heated seats don't turn on
A bunch of other random stuff aswell

Fuses are all fine etc

Anything else to check before I find a bmw workshop that will charge me $$ to figure out?