It's probably the harness I…
It's probably the harness I had a 2007 prius and had the mechanic install a LED conversion kit, and got rid of the HID bulbs. It solved the problem of the passenger side headlight from going out. The dealership said I had to buy their $200 HID blubs as mine could be bad. When HID blubs go out (burn out), they don't come back on. All I had to do was turn the lights off, then back on, and headlights came on. I never had anymore problems with the headlights after he installed the LED kit.