Radio's are really easy to install and troubleshoot, yellow is usually battery constant,you need to have a live 12 volt signal from the battery to the radio.
Red is 12v switched when you turn the key it sends 12v to the radio and when the battery and switched signal reaches the radio it knows to turn on,the yellow wire also works for memory *presets,clock*.
It sounds to me like both memory and switched is hooked up to switched*red*,or your not getting constant 12v signal to the radio.
There is also a gray wire that turned the stock radio's lights on when the dash lights come on and is not needed on an aftermarket radio good place to wire some aftermarket gauge lights though.
These cars,or at least mine did not come with a wire for memory/constant 12v and i had to wire that myself you might want to try running a wire from the positive battery terminal or fuse panel to the yellow wire on the radio with an inline fuse.
Does the radio come on at all when you turn the key? Or do you just get clock, if you just get the clock then the memory wire is wired in the switched and there is no switched signal getting to the red wire.
You can although i would not reccomend it hook both memory*yellow* and switched*red* to the switched 12v source witch will give you a working radio but no presets and no clock.
EDIT: oh one more thing, i can't remember but i think the yellow wire on the stock radio harness is actually the switched 12v source, but i could be wrong my memory is a little fuzzy.
Last edited by wera; 23rd-February-2010 at 04:21 PM.