[Kodiak536]

Those HID bulbs can be a pain. Be sure to NOT touch the bulb part, ANY oil can ruin it. If you did touch it, wipe it with alcohol and cloth before powering it back up.

Switch with known good bulb. If it's still not working, switch to known good ballast.

There had been, on very rare occasion, I had BOTH bulb and ballast go bad.

High beam & low beam use same bulb as far as I know. The ballast supplies the needed power to brighten on high beam...I have 2-35watt ballasts for high beam, none for low beam.

 

[Kodiak536]

There is one ballast per lamp. Ballasts are a problem but a bad ballast will effect only one lamp at a time.

The person that installed the HID system may have also installed a headlight cutout relay. You will need to find that modification and test it to make sure power is being supplied.

That depends on who/where you buy them from.

My system only use 1 ballast per high beam only...2 total. I have no relay harness or relay.

My Tundra also have HID from same vendor but, it's go relay harness and one ballast per bulb since my truck only use one bulb per headlight for high and low beam.

Some do use one ballast per bulb but, not all does.