Make sure all the grounds are on your car's engine.

Make sure your battery terminals are clean and corrosion free. This includes the wires.

Make sure your alternator is putting out more than 14 volts. It's supposed to crank out 14.5v from the charge post to a known-good ground... or you should be able to measure at least 13.7 at the battery when the car is running, 12v with it off. Get your battery tested at Advance Auto for free.

If that stuff checks okay, the problem is somewhere else in your wiring. Wiring problems are 10x more likely on any car that's been in an accident.