Hilts unfortunately if all four lights are lit the entire Ministate antenna is fried. The problem is that the hand controller, the main box, and the internal guts of the antenna are all interdependent so it is almost impossible to tell which of those is the culprit when something like that happens.
The one and only tip I have (I am not responsible if it further fries your system though...
) is to unplug the hand unit, power everything up, and carefully use a jumper wire to short out two pins at a time in the hand unit's socket to see if the antenna changes direction internally.
So, unless you've got the time and money to try different parts on it I suggest just taking it down and junking it.