I don't currently have a voltage gauge hooked up. The amp is only 1000watts rms in a 04 expedition. I figured the stock stuff could handle a short test run. My light dimmed but only when i had it up loud for 20-30 seconds at a time. I also have a us amps us4300x connected to same ground and same power and it has done fine this whole time. Not really sure why it would work for about 15-25 minutes of true listening time and then go into some sort of protection that it would come out of. I would have thought as soon as i corrected to problem whether it be a ground of what not that it would go back out of protection. At least once it cooled down because it was warm but not abnormally hot.