No power to light on back of transom above swim deck

pilawam

I have a 05 320FV, there is a small light on the back side of the transom above the swim deck. I replaced it but still no power coming to it. Does anyone know where I can located where the wires are going to this? What switch and where is this switch? 

Grahamu

On my 342FV in the engine compartment behind the light is a plug, check it for voltage. The switch is on the dash marked transom light.