i have a avh-p6400 and the remote started acting funny at one point it was not working then about 5 minutes later it started back working but i would have to push the buttons a few times about 5 minutes later it started working fine. And now it is not working at all. Anyone know what is wrong.Also what is the system remote control wire?

 

Battery maybe? In my exp[erience when a remote is acting up like that it usually means its not getting enough power to run itself.

Try replacing the battery

 

If you are referring to the blue wire with a white stripe on your head unit, then the system remote control wire is used to hook up audio amplifiers. When your head unit is turned on, there is 12Vdc on this wire, which "tells" the amp to turn on.

 

probably just need to change the battery