1997 Pontiac Grand Am BCM

Sometimes while driving my speedo and tack will just go whacky. I turn off the car and start it again and all is well. 10 minutes later, I'll have trouble with starting it again. Passlock system leaves a lot to be desired. Sometimes it'll start everytime and the very next day it will not start, like today for example. I have the "Theft System" light on constant. It starts for about 1 second and then dies. I hear the fuel pump charge the line when the key is in the ON position. Some think a new ignition is the cure. I replaced it about 4 years ago. I'm told, "in this vehicle, if your key turns the cylinder, its not the ignition". Many mechanics tell me it's the BCM. Then there are some that tell me my vehicle doesn't have a BCM. Can you confirm if my vehicle has a BCM and where I can find it? My Chilton's makes no mention of a BCM. PCM yes but, no BCM :-(