Cindy,
If you have the "moon light" selected on the controller, it may be going thru its 29 day lunar cycle. Try unplugging everything from the controller and it will power down. Power cycling will reset the lunar cycle and the led should work again. As the cycle continues, you should see the led get dimmer and dimmer until it goes out completely. Then turns on again during the new moon cycyle.
If power cycling doesn't make the led come back on when the lights go off, then there is probably repair issue.
hth,
Luis