EDIT: I fixed the issue. I capped the red wire coming from the car's wire harness and connected the red coming from the radio to the yellow coming from the car and now it works perfectly.

I bought a 1990 Jetta last week without radio. I tried installing the one from my old car (Clarion DB185MP) and for whatever reason, the thing won't work. The radio, installed in my Jetta, will eject cds; that's it. It won't power on or play music. The only sign of life I can get is if I put a cd in as far as I can make it go then hit eject, it will take the cd then eject it.

I also have a Pioneer radio laying around but I can't figure out what to do with the orange wire. There's no illumination lead coming from the radio so if I were to use that radio, what would I do with the orange illumintion lead coming from the wire harness?

 

tie it into the orange wire for igniton