Reply to "Dead radio"

Thanks for all the info and various scenarios, as this info really helped. I tested the purple/yellow wire coupling, and that was good with well over 12 volts. Then that yellow wire went though some 1" black plastic unit (yellow in and yellow out). So I wanted to test the yellow wire on the other end of that plastic unit, and decided to try and see if I could test the yellow wire right at the radio itself. When I tried this test it immediately made me think of my IT troubleshooters at work when I would call them with computer problems, and they would say "Is it plugged in?". It appears the vibration of the car over time had made the rear wire connection to come lose on the radio. It was connected (visually), but not firmly pressed in to the hard snap position. When I pressed it in solid, then the face plate rotated and radio works.

Thanks again, you guys are a wealth of knowledge.