if its not the wiring then its the "type of" inverter. Im happy to take a look at it for you if you want to drop by sometime, but I would bet loads of cash that if you used a pure sign wave inverter you would not be having this problem. slightly off topic, can anyone sit in your back seat with the xbox under the seat in front of them? and can you notice the fans in the xbox and inverter when the car is running? reason I ask is several guys have asked me about the under seat mounting but when I tried it all I did was scratch up the top of the xbox, hence it was never properly mounted there in my car