I installed a Clarion VRX755 on my 2005 F150. I hooked it up to my factory amp and sub. Every time I power on the stereo, I get a "pop" sound. It only pops once and goes away. I was told to put a 1.5 k-ohm resistor inline with the remote wire because the turn on is 5 volt on Ford amps and when you put 12 volt from an aftermarket radio on them they pop on turn on.. It doesn't work! Any ideas?