Headlight & Taillight Issues

Both taillights are working when the lights are turned on.

Both reverse lights & turn signals work.

Left brake light always works, right brake light is working when truck is initially turned on but eventually stops working.

Left license plate light is not working but the right one is.

To add even more confusion to the whole thing, the left headlight is not working but the right one is. The headlights have a Morimoto HID retrofit conversion kit that was installed 10+ years ago.

Any thoughts on this? Could the two lights not working be related?

 

Go for the easy stuff first. That would be bulbs, fuses, power (12 volts) and ground at the sockets. As for the headlights, a 10-year-old HID retrofit is about due to have a bulb or two go bad.

 

Does the Left headlight work on either High or Low?
Or never at all?

 

These Factory or Aftermarket lights...

 

HID is aftermarket.