LED light not coming on in MH

I have an invisi brake system. I have had it for about three years. The issue I have is the light inside does not come on when the brake is applied. The audio alert that is supposed to come on after about 20 seconds does not come on either. However the actual braking system itself works fine. The brakes come on in the tow vehicle and release after about twenty seconds like they are supposed to.
I have checked the wiring harness to make sure there are no loose wires.
I have replaced the bullet connector between the tow vehicle and the coach. (At one time I could wiggle the bullet connector and it seemed to work intermittently)
Any suggestions would be appreciated.