TR (transmission Range) Sensor Testing...?

I am just wondering, I am pretty sure that I know that my transmission range sensor IS out, but am wondering if their are ANY ways to test this to be absolutely certain before spending the $80.00 on a new one..???
Anyone know if its possible, if so can tell hom, I would GREATLY appreciate it!!!!

Thanks again!!!

Wes

My TR sensor has gone out twice in the ownership of my 1997 Mercury sable. The only thing that i know for sure that my car did both times was the electrical would do all sorts of interesting things. The power steering would go on and off, the radio and windows would go on and of and the buckle up light would go crazy. The only problem with replacing the TR is there is a special tool required. Other than that I don't know the dealer has a machine that they can hook up to your car.