The last time mowing, it just died. Now, If I unhook the battery and reconnect, it starts but dies immediately, like a kill switch. There is no power to the display after it dies. I can unhook the battery and repeat the process. The display remains off until the battery is disconnected again. I've almost decided it's the key switch, but its odd that I have to remove the battery terminal to reset it. Is there something else it could be?