Ive got an 03 evo 8 gsr with a wiring problem. When the ignition is on everything works correctly. But when I turn the key off it cuts the power to everything. No power locks, no alarm, no headlights. Litterally everything stops working any ideas?

 

Thats weird! Check grounds and fuses, if you turn to ACC do you have power ?

 

Based on the information you provided, I put together the wiring diagram for our car. Since the ignition is in the "OFF" position there aren’t relays or avenues that power can alternately route through. As you can see on the attachment, I colored red the wires that power will travel through to its respective systems. I highlighted yellow the things you mentioned in your post. I circled green the common area that all the items share. I would start there and work from there.

 

Definitely check your grounds and fuses make sure the terminals have good contact with the battery and chassis with no corrosion.

 

I'd say bad ground (since @ key on there is more amperage since more is powered on)

Or bad pin connections internally inside the ignition cylinder maybe?