When i switch on the car (not start) the radiator fan is start working.

it sound to me like you mitsubishi is running hot or the temp sencer is sending a bed signeli would have to know a little more what dose it do when its running and reaches running temp dose it run all the time or dose it turn on and off if it stays on ti could be a short or have been wired strat .eather way not good. (let me know what you find out)