Main fuse blowing in Maxima

I recently was given a 97 Nissan Maxima. The car is in real good shape. The reason it was given to me was, the last owner put a new battery in and when he did he hooked the battery terminals backwards. The car will start but does not have the power that it should. And after a minute or so it will blow the main fuse to the car.I know that I have some kind of short but where I am thinking of starting with the alternator. Anymore ideas.



Thanks

Onece u take the alternater out take it to auto zone to get it check before u replace it

Why the alternator? To see if the alternator is causing the problem, disconnect its electrical connector. If the fuse still blows, it’s not the alternator’s fault. Here is the wiring diagram for the alternator. Click on Fig. 7. http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800764a9
The large wire on the alternator is always “hot” (has voltage). Make sure that the large wire (its usually held on by a nut to the alternator terminal stud) terminal isn’t touching the body of the alternator. Some alternators have plastic washers under the nut. Make sure that the washer isn’t metal. That could ground the wire, and blow the fuse.