No Monitor Light on Roadmaster InvisiBrake Supplemental Braking System

Updated 11/22/2022 | Published 11/20/2022

Question:

The signal light in my coach is not lighting up when I brake. How can I be sure the system is worki

asked by: Terry B

Helpful Expert Reply:

I have attached for you below both a wiring diagram of the monitor light on the Roadmaster InvisiBrake Supplemental Braking System part # RM-8700 and troubleshooting steps from Roadmaster. If the light is not illuminating then you'll need someone to watch the brake pedal in the vehicle as you press the pedal in the motorhome to verify function.

- Make certain the brake light fuse was replaced in the towed vehicle.
- Make certain that the monitor wire patch cord between the two vehicles is securely connected.
- Make certain that there is an electrical ground between the motorhome and the towed vehicle.
- Check for power at the stop light switch, at the front of the vehicle and at the LED in the motorhome.
- Check for power at the back side of the LED light when the brake pedal is held down in the towed vehicle for approximately 20 seconds. You should hear an audible alert after 20 seconds which proves there is power to the harness just before the LED. If you hear the audible alert, verify proper power and ground connections at the LED light. You can also provide positive 12 volts and ground to the LED to determine if the LED has failed.
- The monitor LED is connected to the towed vehicle's brake light circuit. If the fuse in the circuit is blown, the LED will not operate. Check the towed vehicle's brake lights — if they illuminate when the brake pedal is depressed, the fuse is good.
- Was the optional Brake-Lite Relay installed? If so, make certain that the monitor wire is connected to the towed vehicle's brake light wire after the brake light switch, but before the Brake-Lite Relay — connecting the wire anywhere else will prevent the monitor LED from functioning.

expert reply by: Conner L