I have had my third alternator failure in a year on my 1991 Saturn SL. The failure occurs after the headlights, windshield wipers, and heater/air conditioning have been in use simultaneously. I suspect that something that uses a large amount of electricity is damaged and putting enough strain on the alternator to burn it out. I have friends that have the same car and their mechanics have rerouted the electrical supply for the fan. Any information would be appreciated.
Also, a mechanic friend told me that parking on grass leads to moisture damage to the alternator. I live in a rural area where paved parking is scarce. This seems like baloney to me, but maybe someone can confirm this.