Light up knobs

I just assembled a genesis ii e-340. Aside from one minor problem (they shipped me the wrong grates), the only thing I cannot get working are the light up knobs. Pressing the button does nothing. I have gone though the assembly instructions many times and cannot figure out what I have done wrong.

Can anybody tell me what in particular to check?

Never mind.. figured it out. Had the D cells in upside down.

DOH!