I replaced stearing colum in 97nissan maxama the the key switch will turn nothing on what could it be

Yes it is do u think that the factory alarm would have anything to do with it

Or could it be the airbag has been open i baught the colum out of a wreck car

http://www.justanswer.com/nissan/23o17-need-procedure-unlock-anti-theft-security-feature-1997.html ..according to that to re-set the anti-theft use key to lock then unlock driver door, passenger door, and trunk, but that only applies if your red led is blinking.

I'm beginning to think you missed something during re-assembly like a ground. And the air-bag? I know some about them, not an expert by any definition and if I am very reluctant to hand out advice about them and the system. If I did and one deployed without apparent reason I could never forgive myself. But what say we back up some. Do the warning lights on the dash come on when you turn the key to run?