Hello,
I have a 2001 excursion that is on its 3rdaltenatorsince late May 2007. We haven't been able to track down what is causing them to go bad. It has a new starter, new batteries and new battery cables as well. The only thing odd going on that I am aware of is the theft light is blinking all night long. I can't figure out how to get that to stop either. I don't know if this is related or its just some electrical short. Any suggestions?

hey the teft light is supposed to blink.the alternators you maybe putting in could be faulty from the start are they doing a voltage test before and after the alternator is put in to assure a good alt is installed.....you could have a faulty ignition switch....also check the plug going to the alt.you also could have one bad cell in the battery causing the alt to put out max power all the time to make up for the bad cell.you could also have a bad starter needing more than usual power to staart the vehicle hence alt recharging battery...a full starting,charging,and battery system check will verify.......