My D3 was working fine as it should in my 1994 Mazda RX-7. I purchased an iPod cable and took it out to install it. While I had it out, I also performed the bypass by moving the mute wire and grounding it. I put it all back together and everything was working fine.

About a week after these changes were made, the power to the D3 went out while driving and will not come back on (I also noticed the AC stopped working as well when the radio went out). I checked all the fuses including the one on the back of the radio both visibly and with a multimeter. They all are good. When checking the power wires going into the radio the yellow one has a constant power reading, but the red (Acc.) wire does not have any power while the car is on.

I rechecked all my grounds to ensure they were all still making good contact, but still no power. I'm not sure where to look next?

Of the AC also went out with it, I'm positive it's not a problem with the D3... there's a break in the power supply somewhere. Have you checked the fuse panel in the engine compartment as well?

Yes, I checked the fuses under the hood. They were all good.

Usually there are fuses in the cabin too. Check those?

If your cigarette lighter is switched on & off with the key you can temporally connect your red wire there until you find the blown fuse.Get your car manual it will show you where all your fuses are.

Yup it was a fuse in the cabin. I Referenced the wiring diagram and pulled out the ones for the radio. I must have misread one of the sides when i hit it with the multimeter last night. Thanks for the assistance!