no power to the stereo in dodge intrepid

I have a 1997 Dodge Intrepid non infinity stereo that has been radio defective. The car sat dead in my backyard for around 6 months and when I came back to use the car the stereo didnt work. The only power I could get was the clock display which only showed when the key was in the "on" position. I thought the head unit could be dead and I swapped it out only to find the same problem. I have now switched to an aftermarket unit and the same problem is continuing except for the fact that the clock doesn't work anymore, I was thinking this was because the dimmers did not have anything to connect to on my head unit. I have seen that this could be a dead amplifier but I don't even know if this car has one or where it is located. Any advice on where to start would be welcome, I want this stereo to work again.a*^%

I have checked it and it was still good, even put it in another slot and it powered the internal lights.a*^%

The red and yellow wires above are on the aftermarket radio, just to throw this out...Jayce

I just ran new leads to the stereo from the ignition harness, but it still isn't working. I know there is power still so the connections are made because the windows and other accessories are working again. What should I do next?a*^%