MP3 jack directly into stock amplifier?

[Ral]

Would it be possible to wire a 1/8" jack directly to the stock amplifier, bypassing the stock head unit? My stock head unit is not working, and I would (eventually) like to install a blank plate with some gages mounted in it, and run the stereo solely off of an Ipod/other electronic device cheaply and simply.

[Jean]

You'll need to add a switch to turn the amp on/off w/o the stock head unit. Also, how many inputs does the stock amp have, I am guessing 4? 1/8 or 1/4 jacks will be mono/stereo, so you'll need to also wire it to have some front/rear balance for example.

Does the stock amp take high level or low level input? Something else to verify, or the output (headphone) from your mp3 player might be too much for the input of the amp w/o wiring a couple resistors to bring the signal down.