Thanks guys. I thought the ground wire in the back of the stereo was within the wiring harness for the stereo? I'll check there anyways. I will have to recheck the ground I have mounted in the back to make sure it is ground correctly. I know it isn't being touched by anything, because it is between the fender and the battery box and the box is securely mounted. Might need to clean off that area so it has a clean ground to bare metal.
