Oh some diagnostic aid (You will need a volt meter
Go toside (Up on the roof or beside it) and with the Ant-Switch OFF (led off) disconnect the cable from teh antenna.
CAREFULLY Attach volt meter leads (You can hold the negative against the sheell of the connector with left hand and Touch the tip of the center wire with the positive lead. DO NOT SHORT wire to nut/shell) have partner turn on and then off. Observe 12 volts on meter (or not) if NOT you have a cable fault.
Such as that connector in the roof I and one other I've worked on had to replace.