Check fuses with a test light
Was it working previously
Have you had
ICC out
Check accessory relay in interior fuse box
Does radio work but no display if so push and hold main power button for 5-10 seconds
Try disconnecting main plug into front of interior fuse box and reconnecting
Try removing
icc reset plug at rear by pulling it towards you slightly and refitting
Does everything else work ie. wipers flashers etc.
Do reverse lights work