air brake light stays on

The brake light staying on problem was a very simple fix thanks to my new found mechanic here in Ensenada. It was simply a loose connection of the sensor wire at the master cylinder. Corrosion caused the sensor wire to give a false reading.

I agree with Dale...don't ASSUME anything...get it checked and fixed....Dennis

check your air pressure gauge and make sure you are up to full pressure. A dim light usually means you have not built up to full pressure and/or you have a small or slow leak somewhere. I would make sure there are no leaks before driving this unit. Brake failure is never good. Driving trucks is what I do. Never leave a parked position with the brake light on or dimmed period. Try letting the unit idle for a few minutes to build up pressure. If that doesn't do it you need to either figure out why or have a mechanic verify.

The air switch probably has water in it causing the bulb to glow dimly when the park brake is released.
You will probably have to replace the switch, once you find it.