I have tried to hook up my new stereo, a Pioneer P4000, in my 2007 Mustang. I got everything situated for testing, plugged in battery, mounted stereo. I turned on my car, plugged in my iPhone 4s. It starts playing my song and displays the song info, the iPhone wont let me access the menus saying accessory connected, and the volume is up. There is no music coming from my speakers, although a slight fuzz (they're working). I do not have the correct adapter for the antenna, so I cannot test the radio, but when I select radio, I get a lot of static, as I would assume. Is it something wrong with the "mute" cable? I heard that has caused some issues. I have also tried the AUX port but still no sound with a little bit of fuzz. I believe I have everything wired right. What the poo is wrong!??

 

My iPod control says accessory connected and does not allow me to access menus due to the software on the iPod/iPhone. I would look at your manual for your Pioneer P4000, sometimes there is a setting on the head unit that allows you to access your menus directly on the iPod/iPhone. If not the device has to be controlled through the head unit. i Would also ensure that all your connections are tight. It could also be the iPod cable that is causing issues.

 

It ended up that there were two ground wires on the back and I only ha one wired. Silly me. I've never heard of having two ground wires. Why not just have one?