I have a question. Have you recently replaced either a taillight, turns signal or marker light bulb?
It's possible that either the wrong type bulb is installed, or it is not installed correctly, causing the lights to not operate properly. If you haven't, then you likely have an electrical problem of some sort that will require diagnosis by a competent technician.
RepairPal Certified shops can diagnose and repair your 2000 Mitsubishi Mirage. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.