shifter problems, getting out of park...

I have been having problems with the gear shifter on my truck for the last couple of months. I have a 99 Chevy Old body style Z71, automatic transmission . I already changed a "shifter" cable in the steering column, and it did not help. It does not matter if you are parked up or down hill, or on level ground. It does not want to shift out of park. I just bought an actuator, but am getting tired of guessing.

Please help!

Its the brake transmission shift interlock(BTSI). Pull the turn B/U fuse and see if you can shift. You may also be able to shift out of park as you turn the key on and start it in neutral

Its the brake transmission shift interlock(BTSI). Pull the turn B/U fuse and see if you can shift. You may also be able to shift out of park as you turn the key on and start it in neutral

Does it hurt anything to just leave the fuse out, or does the BTSI need to be replaced?

Thanks a bunch for your help!

Something in the system needs replaced, you don't have turn or backup lights with the fuse pulled. I believe the circuit starts at the fuse, then to the park/neutral switch, then to the brake switch and then to the BTSI. You could just unplug the BTSI until you can fix the problem. Check the dark green with white stripe wire going from the brake switch to the BTSI for power with the key on and the brakes applied, it should NOT have power, if it has power the brake switch needs replaced. If it doesn't have power the BTSI probably needs replaced