'92 thunderbird electric problems

i have a 1992 3.8 liter thunderbird. i have replaced my alternator three times in the last four years. i will replace the alternator and it will run fine for about nine months and then just not want to start again. the battery is charged all the connections look fine. im thinking there has to be a bad ground connection but am not sure where to look really. if anyone has any suggestions it would help a lot.

i have a 1992 3.8 liter thunderbird.
i have replaced my alternator three times in the last four years.
i will replace the alternator and it will run fine for about nine months and then just not want to start again. the battery is charged all the connections look fine. im thinking there has to be a bad ground connection but am not sure where to look really.
if anyone has any suggestions it would help a lot.

There is a ground from the passenger side front of the block at the motor mount bracket, and it goes to a screw right by the ignition coil and grounds on the chassis. There's also one on the driver side on the motor mount bracket and I believe that goes to the battery.

The stock ground "strap" connects to the subframe rail on the passenger side and to the front bolt on the motor mount.

Hope it helps.