Motion sensor lights stay on

I have a Halo H1499IC fixture that has stopped working. Two fixtures went out within a day of each other (both @ 2 years old) and used new bulbs but one still will not work (was tested in the other fixture so I know bulb isn't issue). From reading posts on thermal protectors, they sound like they may have given some prior warning either from sound clicking on/off or light working intermittently. Neither of these happened. Is there some other possible cause or do I need to replace the entire fixture? If so I will need someone in as I need to rip open ceiling. Are there any warranties on these fixtures to cover repair - seems 2 years is an awfully short time for lifespan.

I'm thinking (actually, starting to) renovate a dark basement room for use as a "man cave". The room is roughly 11 x 25 (long and narrow) with the final layout to have a home theater setup on the one end, seating in the majority of the middle, and a small bar at the other end. I'm in love with Halogen Pot Lights. We have them in our Kitchen, and I like the light they throw off, whether full bright or dimmed. Retrofitting the basement is going to be a pain and will require (I think) running an additional circuit from the panel, but I'm willing to go through with it. One thing I just thought of though, is the ceiling in the room has a lower ceiling at only 7 feet. What I got to thinking is the heat these Halogens throw off. With only 7 feet of clearance, will I be kicking myself as my scalp burns from the light down there? Any other options (other than florescent, I really want nice dimming for the lights)? Thanks.