RepairPal Certified shops can diagnose and repair your 2003 Mitsubishi Galant. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
If you are getting good battery voltage at the start and the ground is good, it could be a defective starter. Make sure the battery is still charged.
Use this link to find a good shop near you.
https://repairpal.com/repair-shops
Alex