Stock Head Unit Wiring Question...
 

Well basically my pioneer head unit broke and now i'm wiring up a stock S4 headunit in my S5 car. Basically i'm using the wiring harness from the pioneer and cutting the ends and crimping on spade connectors since they fit right on the S4 head unit plugs. The picture below is what i'm wiring up now. It also has the cassette player and equalizer on the bottom. Here are my questions:

1) On the right side, what is the [(a) backup] thing for?
2) I always thought the antanna was the two big black plugs on the left side, so whats the [(a) Antenna relay when radio is on] thing?
3) Can the external amp on the S5 be wired up to this?
4) I only have two rear pioneer speakers now, and no front ones, is there an internal and external amp for this one, and if there is an internal one, is it for the front or rear speakers?
5) Lastly, on the cassette player there is a + battery hookup as shown in the second picture I posted. For the #1 connection thing on there, mine has a plastic cover over top of the spade connector. Is this because its getting power from another source? What does it mean in #3 with backup? Does it mean its not neccessary, and why is there no positive battery connection on the main headunit anywhere? It just needs the ACC one?

Sorry for the long list, but its been like 3 months without a sound system, thanks for the help.

- Brian

http://evansvillelug.org/users/ocelo...res/rx7/hu.jpg

http://evansvillelug.org/users/ocelo...x7/battery.jpg

back up is the battery source for the radio memory and settings. It is looped through the cassette and or eq (if equipped).

as far as an internal or external rear amp, it will depend entirely on what Mazda radio is being used and what the car came equipped with.

Antenna lead is for turning the power antenna up when the radio is on, and down when the radio is off.