Installing new speakers into a Toyota Corolla, including the removal of the current speakers, is a bit more difficult than with other vehicles. This is because the speakers in a Corolla are more securely fastened in place, using rivets instead of screws.
Door Trim Panel
In order to reach the current speakers or install new ones, you need to remove the inner trim panels from the doors. The car has speakers in both the front and rear doors, and removing the panel is basically the same on all of them. Because you're dealing with electrical connectors, disconnect the negative battery cable first. If the doors have manual window cranks, you can remove them by rubbing the edge of a rag behind the handle to dislodge its clip; there are also tools designed for this task. If the doors have power windows, pry out the controls with a trim stick and disconnect their electrical connectors. You need to disconnect the trim panels near the mirror and on the inside door handle and armrest; the mirror trim requires a screwdriver while the others are pried off. The screws for the main door panel are under the handle and armrest panels. Remove them, then insert the trim stick (or another flat tool) underneath the door panel's edge and work around it to disengage the clips. Lift the panel up and off the door, unplug all electrical connectors and peel back the plastic watershield behind the panel.
The speakers in the Corolla are mounted by bolts or rivets. If your model uses bolts, get the right size wrench to remove the mounting bolts and mount them with the new speakers. If there are rivets, you need to drill them out. Use a drill with a bit 1/16-inch larger than the rivet. Drill into the centre until the head comes off the rivet--it should then rotate with the drill--and punch out the remainder of the rivet with a metal punch and hammer. To install a new speaker, mount it in place using pop rivets and a pop-rivet tool.
Before you fasten the speakers in place, you must connect the wires. If the speakers have electrical connectors that work with the Corolla's connectors, this is taken care of. If they don't, connect all the wires by hand. The wires are typically colour-coordinated; the solid-coloured (positive) wires connect to each other, as do the black-striped (negative) wires. To start, clip the insulation so the there is about a half-inch of bare wire lead. If you decide to crimp the wires, twist them together so they connect in a V-like shape and cap them ,squeezing the centre of the crimp connector with a crimping tool. Make sure you have the correct size crimp connector for the wires; they are usually 18-gauge. If you're going to solder the wires, twist them so they form a straight line together. Place the solder on the wire and heat it with the soldering iron, making sure the solder doesn't touch the iron. Use heat-shrink tubing to cover the bare wire, using a heat gun to contract the tubing.