Mine would do the same thing. Somtimes when I would start my car light would come on in the dash, and I would know that it was working. I could use the switch and everything, but when it didn't the switch would not work.
I don't know what the problem was because I finally just pulled the fuse anyway. Now it's like a brand new car. I can finally use 1st and 2nd gear without the F'ing TRAC slowing me down.
When you turn the ignition key to the ON position, the trac, oil press, and oil level lights should go on. If they don't, the wire harness behind it is lose. I just took mine off and re-soldered it.