A step-by-step guide to replacing the factory cassette radio in a Corolla with a mp3- WMA- CD player and radio.
Select the replacement audio. You can obtain CD player with mp3 and WMA from Walmart for $89. The most important features are the ability to play mp3 and WMA format files burnt on a CD but also from a USB drive (thumb drive or removable hard drive). Also has an aux port for mp3 players like the iPOD. This was way better in price features than anything else out there.
These instructions were originally posted by me on http://www.wikihow.com/Update-a-Toyota-Corolla-Car-Radio.
Step 1: Preparing the Wiring Harness
Get a wiring harness or adapter that will allow the car radio wiring to plug into the back of the new radio. These can be found at Walmart for $4.99. Make sure that the plug is compatible with your car (check the list on the back of the box).
Have shown the back of the new radio - the black set of pins is where the included black plug will go to. The free wires on the black plug provided with the new audio system will be connected to an adapter that will plug into the car wiring.
For the Toyota Corolla 1995 wagon, the wiring diagram is as shown below. Your car may differ substantially from this.
Step 2: Connecting the Wires
Connect the wires from the plug that came with the new radio to the wiring harness adapter that you purchased separately. Twist the correct wires together and then solder them (or use wire nuts if you dot have soldering equipment). Cover the exposed wire with electricians tape or heat seal tape. Attached is another table on how you connect your Toyota wiring adapter to the radio plug. Please, do remember that your radio and car will differ a bit.
Step 3: Removing the Old Radio
Remove the factory installed radio (the instructions apply only for Corollas from 95-98). Remove the two screws below the panel. Have shown a picture with the location of these screws. Remove the control knobs for the AC and the fan, etc. These come off pretty easily with a gentle pull.
Use a thin blade (metal spatula) to probe approximately 2/3rd of the way up and try to pry the sides out. The metal blade will disengage the clip on each side. Took a bit of gentle effort but it did pop out. The location of these clips is just below the vents.
Lift the panel up, reach under it to carefully remove the plugs on the right hand side that connect the defroster, the clock and the hazard flasher. The plugs can be removed by squeezing a release tab on the plug and then gently pulling them apart.
Remove the radio - two pairs of screws on each side of the radio hold it in place. Remove these (and hold onto them because you will need them later on) and then slide the radio out.
Step 4: Pull Out and Disconnect the Old Radio
Pull the radio out towards you. Remove the antenna wire from the back of the radio. Remove the pair of wiring harness plugs that go to the back of the radio by pressing the release tab on the plugs. Remove the radio.
Step 5: Transfer the Side Brackets From the Old Radio to the New.
The sides of the radio has mounting brackets. Remove these from the factory radio. Make sure that you mark which one goes to the left of the radio and which one to the right.
The walmart radio comes with multiple holes on it's side - some of which aligned with the mounting bracket. If you try to attach these, tiny metal studs on the brackets will interfere with the attachment, so grind them down with a dremel tool or file. Screw in the left bracket on the left side of the radio and the right bracket on the right.
In the images below, the black bezel has not been taken from the radio.
Step 6: Connecting the Wiring Harnesses
Get the wiring harness that you had prepared and plug the white ends of the harness into the wiring harness that you had removed from the back of the old factory radio and that is still poking out where you had left it. Connect the black end into the back of the new radio. Also connect the antenna wire into the back of the radio (large round hole).
Test the plugged in radio to make sure it works and you can hear sound through the speakers. See if the radio lights (LED's come on - that is power is getting to the radio, see if you can hear sound from all 4 speakers by playing with the balance and fade knobs (that is all 4 speakers are connected correctly) and see if you can tune to FM and AM stations (confirming that the antenna is connected).
Step 7: Slide in the New Radio
Slide in the radio till the side brackets are aligned with the mounting holes and attach the radio with the original screws used to attach the factory radio.
Step 8: Finish by Attaching Panels and Knobs
Test the radio one more time just to be sure. Now attach the central panel that you had removed by a) placing it in approximate position, b) attaching the three plugs to the panel, and c) lightly tapping into place at the location where the clips are. Once you have the panel in place, attach the two bottom screws. Attach the knobs and the AC switch, ... and that's it.