DIY AUX cable

[flg8r90]

I read in the electronics section that you can make an AUX cable for the CD business radio. Can it be done for the cassette version ? I have a 2003 cassette radio with 6 disc changer in the back. I'm a little confused that someone said it can not be done for vehicles before 2004. Is this true ?

I found this and was wondering if anyone has tried it ? Supposedly this hack only works for non-aux radios.

Easily Add an Auxiliary Port to an Old Car Stereo for About $3

Thanks