What can you do if the ignition key on 1999 Tahoe is stuck in the on position?

This is a tough fix... and a small star driver (similar to torx) is needed. I managed to find one at a computer store. There are several spring loaded pins in the key mechanism. You have to actually take out the key receptacle. It has been a while since I di this, but I managed to fix it. After removing the key receptacle, one of the pins will be broken. You can remove and discard one or two pins without a problem. Mine worked fine for a few weeks, then locked up again. I called a mobile locksmith to come out. He fixed it and charged me $200.00. Probably less than dealer charge.