Battery died then - SERVICE 4WD LIGHT ON!!

[dandbmartin]

I have a 2002 Trailblazer LTZ. Last week I left the key on and the battery went dead. After jumping it off the SERVICE 4WD light came on. Now I can not switch from 2WD. The lights on the switch come on when you first start the car but then they all turn off. I have read a couple of posts with similar problems but no one ever posted the solution. Please help!!

[Vartz04]

i have the exact same problem, switch wasnt working before i disco'd the battery, then i put it back on, the service 4x4 light was on and the switch started lighting up when i first started the car. No idea what it is, from what i have gathered tho its more than likely the TCCM