Ford Fiesta no lights on dash except oil light

I would first check for power at the plug to your cluster this will tell you if it,s a power feed issue or the cluster .then follow the wiring to the next junction connection and carry out continuity test on each power wire to ensure no breaks .you will require a wiring diagram to fault trace this.If this vehicle is networked it could be something else that is bringing the network down a wiring diagram would tell you this also.If it is running a network there could be a short which is bringing down the power level .I do not want to go too in depth .as like I say the correct model year diagram will tell you and just try following the wiring to source firstly.