I have a 2006 Magnum RT. While driving the dash brake light keeps coming on and going off. I doesn't appear to be the parking brake switch as it goes off and on while driving with the parking brake off. I understand that this light is also connected to the master cylinder switch. If I unplug the master cylinder switch the light stays on constant. If I bypass the switch the light stays on constant. Not sure whats going on. Could it be the master cylinder switch? The master cylinder is full.