Mach 460 on 2003 - problems with speakers and custom radio
I just purchased my 2003 and found the sony stereo was not putting out sound well. If I turned everything to the front only the left front would work from tweeter and the back non-tweeters would just slightly come on. It would do other things that didn't make sense when you changed to other zones.
I pulled the radio out, I didn't see anything strange looking. So I disconnected all the speakers and worked on one at a time. Long story short, I don't think they used a comparable convert kit on the wires when they put it in. It only had two plug wires for the subs. The radio has 4 so just for fun I sliced in an addition plug wire to each harness wire, i.e, I made a splitter on the white and red jacks. Plugged it in and all speakers came on and changed zones correctly.
I really didn't think that would work but it did.