Just did a install on a D3. Everything works find except I have a pop in the sub evertime I turn on the unit.

is it a factory sub or aftermarket?

Factory

Bet its a Ford, Put a 2-3k resistor inline with your turn on wire (blue witha white stripe)

your fact system only needs 5 volts, your unit puts out a 12 volt signal

Thanks for the reply. Yes it is a Ford. That's what I thought was the problem so I tried a Voltage Regulator and got a pop with static. I will try the resistor. Thanks