Alternator problem ?
Red battery light flashed on and off, window would
not roll up. Pulled over turned car off. Tried to
restart but nothing. Old battery was severely
corroded. Bought new one and cleaned battery
cables of corrosion. Car started. Had alternator
tested at auto store. Was told not working. Took it
off and to another auto store to test it off car and if
needed buy a new one. They tested it 5 times and
said it passed each time.
Should I just buy a new one and hope for the best?
I would say Alternator if you replaced the battery and cleaned the connections
More than likely it is an internal problem with the alternator, like the voltage regulator, the alternator could still work on a test stand showing out-put, but most don't test for the regulator. Also it sounds like the battery cables should be replaced.
Search BMW 5 Series Questions
BMW 5 Series Experts
Related Models For Sale
Used Cars For Sale