Why doesnt the anti brake lock light want to come on?

What is your question?

I went to get a brake and lamp inspection done and the guy said it wont pass because the anti brake light will not stay on. The car was off, he then set it to reverse, and tried to turn the car back on. The car didn't turn over, but all the dash lights came on and stayed on except the anti brake light. The guy then told me it could be as simple as a sensor or a light bulb, or it could be something worse, but the light needs to stay on when the car is set like this or else i cant pass you. I cant really afford to much and i need this to be done asap so i can finally get this thing put in my name. If anyone knows what to do, or if theyve run into a similar problem and have a quick fix, please, Id really appreciate the advise. Thank you.