Q: How do you remove and install door speakers, rear quarter speakers, and a trunk-mounted subwoofer speaker on Ford Focus?
A: To change the door speakers begin by taking off the door trim panel and then removing the four cross-head screws which pulls the speaker from inner panel for the rear speaker of the 3-door model. To remove it, loosen the screw on the bottom and pull off the electrical connector followed by the speaker and reverse the above in case of re-installation. For rear quarter speakers in two-door models, there is a C-pillar trim panel bolt cover that has to be unbolted followed by unbolted of the C-pillar trim panel and then pulled inwards. In case the retention clips became stuck, take them out and place into C-pillar trim panel then they must be reinstalled. Pull and take out the door threshold scuff panel and deal with any clips, if necessary, in the same way. Free the door weather strip, get rid of the lower hinges and child seat anchorages, plus rear seat backrests, as well as get rid of the bezel from the seat belt sender. Removing the quarter trim panel requires pulling it away from its clips, after which the speaker connectors are unscrewed and disconnected, the trim panel is fastened in reverse to the initial process. For four-door models, first, disconnect the trim cover at the D-panel screw and also the screw freeing the D-pillar trim panel. In the trunk, to unlock the seat side bolster upper retainer, further take out the rear seat cushion and the rear seat side bolster panel lower nut in order not twisting seat belt in the process of reinstallment. Disconnect and unbolt the lower seat belt; free the door weatherstripping; unfasten, but do not take out, the screw cover and screw for the upper and lower quarter trims, as well as the upper and lower quarter trims themselves. Treat any jammed clips as described above then undo the screws and the quarter panel speaker and disconnect the wiring before finally tightening the screws and putting back the quarter panel speaker in its proper place. For the subwoofer trunk-mounted speaker the point one should remember is that the whole speaker, amplifier and enclosure must be changed simultaneously. First Pop the left trunk trim panel, next disconnect the wires from the subwoofer, then un bolt the four screws to remove the subwoofer assembly and at last, install it in the reverse manner.