You should have a black, yellow and green wire, Black is the main power wire and comes from the main switch, then yellow and green come from the hi/low switch, Green is low, and yellow is hi. I know on mine the black wire was in a bundle with another yellow and a brown wire, then the yellow and green where in a separate bundle, but it should be easy to trace back to the hi/low switch. If you wire both yellow/green wires to the light, then the light will work with the switch in either position.
Levi