I have a 2005 X5 with 4.4, my trifecta lights was caused by a broken transfer case actuator gear (plastic). Not sure if your 2001 is the same, but worth checking. You'll usually hear a clicking sound when you turn the car off (worm gear skipping over broken teeth on plastic gear). Not hard to check, actuator held on side of transfer case with 3 screws and unplug wire, looks like a power window motor. I had 2 Odometer Gears brand gears go bad, but replaced with this $10 Amazon gear and has been working for 3 years https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
The Odometer people were great, gave me a free replacement when the first one went bad, but this Amazon one is working.