how ca i fix fan heater on my Ford Transit 1988 2.5 d?

how ca i fix fan heater on my Ford Transit 1988 2.5 d?
The fan is located in a cabine behind a cooler and my full question is how can i get to him? Do i have to move cooler or all console inside cabine so i could move out fan? Or maybe is a problem in a wires? Maybe someone knows where power wire ends?
please help someone! ty