4low issues

2000 blazer lt, 72000
While driving, 4 lo light flashes and tries to engage. When placed in park or neutral, 4 low engages and it will not go into 4hi, 2wd or auto 4. I have to pull the fuse, put it back in to get it to switch back into 2wd. I have to leave the fuse out to keep it from engaging in 4 low.
Any advice?

Thanks

2000 blazer lt, 72000
While driving, 4 lo light flashes and tries to engage. When placed in park or neutral, 4 low engages and it will not go into 4hi, 2wd or auto 4. I have to pull the fuse, put it back in to get it to switch back into 2wd. I have to leave the fuse out to keep it from engaging in 4 low.
Any advice?

Thanks

Well, 1st off, the 4l0 WILL NOT engage when the truck is moving over 3 mph. It can only engage in park or neutral. That said, it sounds like your TCCM is flaky. I would grab one from a bone yard. This is indicated by pulling the 4wd fuse correcting it. (It's like pulling the battery cable)