After I came in this afternoon and shut down, the over volt/under volt light started glowing and got brighter as I got out of the cockpit. I cycled the master and it did the same thing. I popped all the circuit breakers and turned the master on again. Once again the light would go off with master on and the when the master is turned off, start glowing and get brighter. I reset all the circuit breakers and cycled the master several more times and it finally stayed off. Battery indicates 12.6 volts. Any suggestions as to cause? Master solenoid?