A few weeks ago I noticed my truck beginning to start weaker than normal. One day it wouldn't start at all but the positive terminal on driver side battery was loose (dual batteries). After tightening the truck cranked and got me to work. I changed the driver side battery out for a brand new one from Napa. Truck cranked but when I got off work I had to jump it off. After that the lights and all electrical would come on but not turn over. Changed one of the 175 mega amp fuses that is on the passenger battery and nothing. All the connections are clean and tight. Replaced the whole starter. Finally changed the passenger side battery and the electronics worked. While tightening the terminals my socket wrench fell and touched the three 175 mega amp fuses on passenger battery causing a lot of sparking. After that I'm back to having no power at all. Old battery is swollen. The wires show a bit at terminals. Terminals don't sit all the way down on post on the Napa battery. Thanks
My car has 90000 miles.
My car has an automatic transmission.
This sounds like some kind of an electrical short somewhere or potentially a faulty alternator. If there are any check engine lights on I would suggest having the truck diagnosed with a scanning tool which would reveal any fault codes. With these codes it would help to narrow down specific components that are not working properly. I would also have the alternator tested to be sure it is charging the batteries as it should. If you need help with this, contact a certified technician, such as one from YourMechanic, who will be able to diagnose the source of your electrical issues and help you fix them accordingly.