I just got my D2 in today, but I didn't have a chance to read the manual yet. From what I read, I gathered that the bypass method for the D3 works for the D2. But what is the mute wire supposed to be used for when installed as it is intended to be?

It's for external equipment like cell phone interfaces, onstar, and things like that to be able to mute your stereo when they have something to say. The wire is pretty much obsolete now due to the fact that most things that need to mute the stereo nowadays connect through the IP-bus port which it uses for muting instead.

Cool! Thanks.

I was going to give a shorter answer.....

mute wire is for bypass. nothing else

i used to wire for my rear park assist when the car is in reverse the radio is muted so you can hear the back up sensor.

i used to wire for my rear park assist when the car is in reverse the radio is muted so you can hear the back up sensor.

I have a 2004 Expedition with park assist and would like to do the mod you mentioned. What should I connect to the mute wire to attain the same results?

The same thing you hooked your reverse signal wire to. Or if you never hooked that up, it's the wire going to one of your reverse lamps.