I have the Ford Nav headunit (did this with the Shaker too) and an aftermarket amp/sub. Works very well except that every time the headlights cut in or out (auto headlights) the amp thumps pretty loudly. Very annoying. Is there a known issue/solution to this when adding an amp to the factory system? Can someone point me to a thread where this is discussed or solved?

Thanks!

 

Here is a link which describes a similar problem with an aftermarket headunit and factory amp, not sure if it applies in your situation though. I think most people who install aftermarket amps usually replace the head unit as well, so it might be hard to dig up information on your problem.

http://www.dennisjudd.com/archives/000947.html
http://www.radioshack.com/product/in...tId=2062599&cp

Tim