New battery & fuel pump. Hours later car starts and shuts down 3X in a row. Finally it starts, 48 hours later, won't start at all, hear a click. Windows, lights, radio etc work, can hear fuel pump humming from back seat. What could be the problem now! When I had the diagnostic, turns out the mechanic left the battery connectors loose in addition to my new battery being drained...fixed the pump, jumped the battery...let it charged. Then hours later the before mentioned problems started. One opinion is the loose battery caused a short in the electrical system. Going to check the fuses and pray that is not the case. Any thoughts please.
My car has an automatic transmission.
Checking all the fuses was a good move. I would also want to put a scan tool on it and check for diagnostic trouble codes (DTCs) as well as seeing the data that the computer is seeing.
A fuel pressure test would be a good idea to verify correct pressure and so that you’d be able to eliminate that possibility. It should be 58psi on your Magnum.
I also recommend getting your battery tested (I know, it’s new, have it tested anyway) and be sure it’s charged to at least 75%. And yes, loose battery cable connections can result in electrical problems.
If you need some assistance with this, consider enlisting a certified mechanic who can perform the checks I’ve mentioned and diagnose your starting issue firsthand. The mechanic can then perform the necessary repairs once the problem has been isolated. Good luck.