New to posting, not new to BMWs.

I have been researching everything i can on how to figure out the cause of the electrical problems plaguing my beloved X5 4.6is (AKA Darth).

Initially, the radio started buzzing, then the battery died. I had the battery replaced by BMW-certified mechanic which resulted in the loss of the display screen, radio, amp & nav. Note: I had the car 4 years before I had to replace the battery and NEVER had a problem with the nav or radio or even the display screen before replacing the battery.

Fast forward 6 months and miraculously the display flickered to life last Friday (despite the mechanic telling me it was disconnected) and the nav started working perfectly but radio remained dead. 24 hours later Darth demanded the radio code. Got the code, drove him for a day (errands). Next day, went to drive Darth and all the interior and external lights flashed and clicked and Darth died. Current Status: Paperweight.

According to the research, my next moves should be as follows:
  1. Charge the battery
  2. Check the alternator (even tho it's less than a year old)
  3. Make sure it goes to sleep
  4. Check the fuses (specifically #73-75)
  5. Check the FSR
  6. Hire a demonologist


Am I missing any steps? Are there any other areas I should explore?

Thank you!