Its under the panel directly above the passengers knees below the glove box. 5 minute job to change but check first it could be the resistor that's gone not the fan. Also you can replace the brushes in the fan motor separately if its those. Did mine recently for just over £75 new fan and resistor, plenty on flea bay or ECP
Did mine used to squeak took apart cleaned now quiet as a mute mouse, you could try just pushing base of spindle sometimes makes cleaner contact with brushes