I'm working on installing my avh-p4450bt. I got the metra dash kit and the wiring harness, which included the red wire with out instructions in the first picture.

My questions are what is the red wire for, and in the second picture, obviously one of the connectors is for the antenna, but what are the other two connectors for?

 

Not sure about the red wire but in the second pic, one is antenna and one should be CD changer.

 

any chance you know what the plug circled in blue is for?

 

The connector circled in blue is for the inputs/outputs circled in red in the below diagram from the rear of your Symphony.


If you didn't get the following connector with your Metra kit then you still need this one.


Doug

 

i got all that and i have 3 different large plugs. here is a picture showing that. ome is a dark red that is plugged in and all seems to be working minus the radi since i dont have the antenna plugged in yet.

 

finally got the antenna adapter, but I'm only getting 2 out of the 6 stations I usually listen to. all the others are just dead air. all my connections looks correct. The adapter I used is the Scosche Universal Antenna Adapter from walmart. Scosche Universal Antenna Adapter: Auto Electronics : Walmart.com

it says audi up to 92 but it has the right ends on it. could that be the issue, or does anyone have any other ideas? or could it also be part of that mystery plug circled in blue?

 

the antenna adapter i bought from crutchfield in the link below fixed the horrible reception issue. I hope the next person that has this issue finds the post in their searches.

I'm still not sure what the other connector was for but the stereo seems to be working.

Antenna Adapter Works with select 1994-up Volkswagen and Audi vehicles (Motorola male to OEM antenna female) at Crutchfield.com

 

The dash install kit I ordered had what I feel is all the wiring but I have basically no stations

 

do you have a link to what you ordered? i ordered the dash kit, and the wiring harness but i needed the antenna adapter i referenced in post #7

 

Someone had mentioned the antenna uses a powered booster since there is no aerial. I think power needs to get to it via the adapter and the oem harness. It may use the one wire sticking out of the orange connector that is unused. This is all hearsay so you will have to dig for this info.

Doug