2009 x5 48i - issue started with key fob not working.  Simple fix, fuse 127.  That started fixing it for roughly a week, but not it only lasts seconds.  The radio randomly works.  The airbag warning is on.  Today the gf texted me that the awd gave a warning as well as the backup camera stopped working.  Last weekend, we found the battery was dying (down to 100 CCA).  Swapped it out, and everything worked for 2 days, except the airbag warning which will likely need to be reset.  Does anyone have an idea if all of these could be linked to something?  All I can think of is one of the computers may be going bad.  Thanks!!

Electrical gremlins can be a nightmare, asuming that there is no other cause water ingress/spill in the boot area there is a lot of sensitive bits in there. Most electrical issues with the X5 are caused by low battery voltages, even though you have fitted another battery. You say you "swapped out" the battery was that for new or another battery? Have you checked battery voltages since? You should have 12+ ignition on engine off and 14 or thereabouts engine running, even a new battery can fail, is the battery correct for your car it should be 92Ah AGM if the battery is correct and healthy but voltages are down is it an alternator problem? I cant recall the year when the battery needed coding/registering to the car this could be another cause. With my older X5 the odd behavior I tracked down to the main earth point in the boot the mounting bolt was rusty I cleaned and refitted it problem fixed.

Dave