I just tried installing a CD player into someone's 1995 Mustang with the Mach stereo. Everything went well, except if I put it to accessory, wait a second, and then turn it on, it pops really loud. I heard something about using a resistor, which I tried and it still does it. Also, she has wires run for a aftermarket amp as well. Could it be that I am a dumbass and wired it to the aftermarket amp remote wire, or is it the resistor? Thanks in advance.

 

I am having a terrible time deciphering your post. Try rephrasing it stating exactly what she has in her car.