Troubleshooting A Roadmaster InvisiBrake Compressor That Continuously Runs

Question:

Invisibrake was deadfoot , I replaced a 50a fuse on main panel of my E450. Discovered the battery fuse to invisibrake was blown, as well. When replace that one, the compressor runs continuously. Doesnt seem to pressurize to stop it. What seems to be the problem? Thanks.

asked by: Steve K

Expert Reply:

In the installation instructions for the Roadmaster BrakeMaster # RM-8700 there are two fuses wired to the air compressor circuit. One 20 amp fuse on the power wire of the battery, and a 10 amp fuse connected on the blue wire that runs from the ignition switch to the air compressor. I've included a wiring diagram to help you check these fuses and ensure they are in working order.

As for the compressor continuously running, this could be an indication that the breakaway switch has an issue. If the pin is missing from the breakaway switch or there is damage to the switch or its wiring the system will think that your vehicle has broken away from the motorhome and keep running the compressor to ensure that your system is braking the vehicle so that you can safely pull over.

If the breakaway switch is fine then let me know and we can keep troubleshooting.

expert reply by: Kevin C