All of mine r making a ticking noise but still dosnt work. The off light stays on.

 

I checked mine and they all make a ticking noise but still doesnt work. The light stays on inside the cab.

 

Push the button to the "on" position...

 

I push the button but nothing happens an the light stays on.

 

First off - nothing dangerous about putting truck into reverse with the engine off - its not going to roll anywhere in gear.

You may hear ticking from all 4, but make sure that they are all ticking strongly/audibly. A faint tick indicates a bad sensor(as does no tick). Swap it out with one that is working to rule out bad wiring/harness.

If all 4 are ticking strong and system still won't work, then you're likely looking at a module failure. Never hurts to try a reset by doing a battery disconnect for 10 mins. I seem to remember reading somewhere that if you hold the button down while turning on the ignition, that the system resets as well. Play with it and see.