I thought the same thing, however the wheel lit up no problem when I installed colorpearl. I think something is messed in the software. I am afraid to upgrade to the lastest software since the phone is unlocked, I really don't want it to lock it.
IF I was to upgrade, where can I find the correct software for a unlocked Tmobile 8100
Not familiar with colorpearl since its N/A for the 8130, but it may possibly bypass the keypad light sensor if it lights the trackball everytime you touch/press it regardless of ambient light. Have you tried a battery pull just for grins?