No its impossible!
To change car stereos, you will need to remove the bezel or cover from the stereo in the vehicle. Then, pull the stereo out of the dashboard and remove the wiring harness. You can then attach the new stereo to the harness.
http://www.modifiedlife.com/1988-toyota-tercel-car-stereo-radio-wiring-diagram/ Change the year in the link to your Tercel's year
color code of car stereo wiring
http://www.modifiedlife.com/request-a-hyundai-car-radio-stereo-wiring-diagram/
What is the wiring diagram for the car stereo on a 1997 Ford thunder bird
colar code for sony stereo car
http://www.modifiedlife.com/car-stereo-wiring-diagrams-and-car-radio-wiring-diagrams/this is the best site for diagrams for stereos, enjoy!!!
http://www.modifiedlife.com/2005-hyundai-accent-car-stereo-radio-wiring-diagram/
Car stereo wiring color codes for a Mustang can be seen on a diagram. The diagram may be found in an owner manual or request from the stereo company.
http://www.modifiedlife.com/1993-pontiac-bonneville-car-stereo-wiring-schematic/
That depends on the amount of pins the old and new stereo have - the "pins" are where you plug your wiring into in the back of the stereo and not all stereos have the same number of pins. (But wiring adapters with the suitable number of pins can be bought)
the ACC wire from the stereo is connected to constant power (+12V)