I just re-installed my Ice Cap 660 and T12 lights into my new canopy and now only one light, lights up. My wiring is the same and I changed the new buld that's not lighting with one of the old ones and nothing. Is it possible that I've got a wire loose in the end caps? Can you tighten these? Thought I'd ask before I start dismantleing the lights. (I've got them installed on plastic conduit fittings to lower them enough to match the elevation of my MH reflectors) Thanks for the input.