Charade brake lights problem

Hi, i have problem with my Charade brake lights. I noticed that they dont work and changed bulbs there but not working. Then i noticed that brake light fuse is broken. Got new fuse and lights works again but when i start engine and push brake pedal it burns fuse again. When the engine is off they work just fine. So whats the problem? Is it hitting ground somewhere?
Car is Daihatsu Charade 1.3l 1989

Does the fuse also blow if the ignition is on but the engine off?

Sounds like the wires for the brake lights either make contact with other wires or with the car itself causing overload on the fuse. Best bet is to trace the responsible wires for breakage or damage.