Fuse is still busted when you turn on the power supply?...if yes, mosfet should be the problem. if fuse is ok upon power on but still no output, switching Ic might be the problem...But still check the connection between your board and halogen lamp, because that in that kind of circuit, usually there is no voltage detected in halogen lamp terminal if there is no load attached to it, meaning your connections must be good and your lamp must be ok before you could detect a voltage to lamp's terminal...
