:iagree: with all the above that the charging system is causing your idiot lights to turn in and off intermittently. The X5 electronics is highly sensitive to voltage fluctuation (welcome to 1999 technology).

As posted, having your alternator tested (load tested with a carbon pile tester- image below) will show that the regulator is not functional as designed. As mentioned the brushes wear out internally some where between 80-130K depending on electrical load from stereo, AC, wipers, heated seats, etc. You get the picture.

Bottom line: test, repair, or replace. or wait to be towed off the interstate. Your options, Your life.