xg ute( ef motor) has got big problems, it keeps blowing the computer and bcm's caused by water which we first thought was a windscreen leak as we know it leaks, now the mechanic has told the owner it has a planum box?? or something called similar to that, that is buggered and will cost 4-600 to replace, now we have no idea what part this may be and it isnt the heater box because theres no coolant leaks. , what could this "planum box" be?
thanks

edit-found out its the bit along the front where the water drains off the windscreen and its normal for them to rust out at this age,

commen problem on XD-XG falcons. the only way to fix it is to remove the dash, heater box, windscreen, wiper motor and drill out the spot welds that holds the cowling panel in place and repair the rust.