Just got the TiVo Slide Remote now that the price went down (best remote yet IMO). From what I understand, there is a sensor that tells when the lights go out, which then automatically turns on the backlight. The only time the backlight goes on for me is when I either press a button or slide open the remote. I tried holding the TiVo Button + Thumbs Up until the status light flashes three times. According to the instructions, this should turn on the feature (using Thumbs Down turns it off). However, there's no change. Is my sensor broken? Or am I missing something here?