I have the attic HID kit (fitted when I brought car) but noticed recently the passenger light doesn't come on when I turn them on, I have to wait to the driver side one to warm up to full brightness then turn them off and on then both work!

Dodgy connection? Bulb on way out?
Any ideas?

 

Odd. Have you looked at the wiring? I'd be inclined to swap the two ballasts over, see if the problem shifts to the other side? Then it's a new ballast.

if not, do the same with the bulbs: swap them sides, see what the effect is?

 

Yeah I think I'll have to try that. It's just odd that it works fine once warmed up. Makes me think it might be ballast. Any idea how much a replacement would be?

 

Could be wiring. A cold HID takes around 10A for a short period during start, so it could be that the wiring to one of them is dodgy.

 

Thanks Tim, think I'll remove the headlight and replug them all

 

Look for loose, wet, or corroded connectors too.