Hugo, before you replace it, try swapping the right ballast with the left one. If the problem moves to the opposite side, you know it's a bad ballast, if it doesn't, then you have either dead rings or faulty wiring. The fact that both of the passenger rings went out at the same time would lead me to believe that it's either a bad ballast or the wiring came loose. Check all of the spliced wires on the passenger side, wiggle them around, maybe re-twist them. Also, since you purchased yours from understeer, the ballasts might not be "inside" of the headlight housing. Just look for a little black rectangular box with two white wires coming out of each end of it. It should be spliced into your corner light wiring.
FWIW, don't listen to Marv, he doesn't know what he's talking about
They're not caller transformers, they're called ballasts or ignitors
Just make sure you're grounded first
