How do you change an alternator belt on a Audi a4 1.9tdi?
take the old one off and put the new one on
Can an alternator fall out of a car?
Sure, if the bolts come out the alternator can fall out.
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possible but very unlikely if installed correct in the first place
Why would the headlights drain the battery on a 1996 Lexus with a new alternator?
The new alternator is bad happens all the time.
1995 jeep grand Cherokee will not charge battery although Alternator has been tested good?
Try removing the battery cables and cleaning both terminals as well as the cable connectors. Try to test the electrical continuity of the cables, one may be broken inside it's insulation, making it invisible. Have the battery itself tested, it is not uncommon for a battery (especially an older one) to just quit.