Yes, I know exactly what is wrong.
The two lights that are flashing are actually flashing the thin running light filament. Take a wire from the battery negative, and connect it to the side of the bulb. If everything starts working again, it's that ground wire that is not properly connected to ground.
What happens is like this. The current comes to the base of the thick filament of the bulb, then cannot exit out the side and go back to the negative because that connection is not there. So it then goes backwards through the thin running light filament and over to the other side and through that running light filament, then it goes out the good bulb on the side and to ground.
The best way to prove this is what is going on is to take the red lens cover off, and look at the bulbs and the filaments inside them. In your case, the current is going through the thick brake/turn filament, then the thin filament on both sides. You will likely see the thick filament barely glowing, but the thin ones are more resistive to current so more voltage drops across them and they glow brighter.
