factory amp popping on 03 navigator

Hey I need a quick question answered. I just bought myself a new 03 navigator. I went to put my avic d3 in and I am having a problem. When the radio turns on It pops the factory sub. Even with the radio off and I test it with my power probe it stills pops. When I plug in the factory radio there is no problem. This is the first navigator that I worked on in my past 10yrs of installing. I want to leave my factory sub in till I finish the custom enclousure that I am working on. And I am not in a rush to finish it because of work and vaction. I can't just have all highs and no bass. I putting up with the pop for the last three days and its killing me. TIA

never mind I figured it out, factory output was 5 volts. a couple of resistors and woalao. Dam fords

how do you like the d3 i am considering purchasing one

its great. I am testing it out as we speak. Thanks for the pm. The d3 should be out in the next 2 weeks. I have pics of it up soon as I can. Its suppose to be a display model but I have to try it in the car, lol