At slow speed, suddenly the power steering quit. Then I saw that the battery light was on, no alternator output. Then I smelled rubber burning. I shut off the motor right away.

It was the serpentine belt. I looked it over where it was visible but saw no obvious problem. I tried starting it up again and the belt started smoking before I had time to see where. I decided not to destroy the belt by troubleshooting it, shut the motor off again, and went to get our big trailer to tow the X5 home.

An hour later I jockeyed the X5 to put it on the trailer. The power steering worked for a few seconds, then quit again and the battery light came on. Once the trailer was in place, I started the X5 up to drive up the ramps, and the problem was gone. I had power steering and the battery light stayed off.

WTF could do this? Some component on the serpentine belt must be seizing up. I am going to leave the X on the trailer and take him to the indy tomorrow, if he has time to take it.

This is not a problem I have ever had before with a BMW or any lesser car. Weird! Has anybody BTDT? (been there, done that)

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Reno, France near Deutschland
E70 40d LCI nicely kitted out but no bling stuff
E53 3.0d facelift with manual gearbox
E39 530i facelift with manual gearbox
And a couple lesser vehicles of necessity