On mine I have not did your voltage drop check yet but I did go to the junk yard and grab 2 flashers and a CTM just to try it, I figured the chances 3 flashers are bad is slim. Nothing changed on mine radio stays on. I did take notice tho with the aftermarket radio installed key off if I turn the left or right turn signal on the radio will shut off. Key on and turn signal on radio stays on like it should.

 

That points back to the combination flasher...so when the turn signal flashed on, the radio would turn off, and turn signal flash off, radio back on? Cycling back and forth?

If so, that goes back to the combination flasher with a transistor or diode leaking when it shouldn't.

 

No, with the key out the radio doesn't cycle with the flasher, signals don't flash either, its just like a switch when you turn the signal on radio just shuts off. If the key is on signals work normal.

 

I think I may have figured it out finally, at least for mine. I was messing around with the wiring and for some reason decided to connect the illumination wire to the switched power wire, to my surprise everything works aftermarket radio shuts on/off with the key etc. Now theres only one problem the button lights on the radio always stay lit and screen is always in the dimmed down mode. I decided to go back onto the autozone wiring diagrams which actually seem pretty good and looked at a 2002 model year and the there are two wires that feed the radio, a white wire called headlamp switch output and also the orange wire called panel lamps driver. The 2004 model year only has an orange wire label panel lamps feed on the radio. The white wire s still there but it looks like it just goes to the instrument cluster. I don't know if magnethead can confirm what I'm seeing.

 

sorry about last post thought I was on to something, instrument cluster lights just stay on doing that.