If I have already installed my Alpine 9857 without the DCI will I need to use his harness to make the whole thing work?

 

It depends on how you installed your HU.

There is nothing special about Modifry's harness. It is provided as a convience. (IIRC.)

So if you installed your HU with a harness, you should be able to easily splice in the DCI.

 

i did use a wire harness, but there were two plugs behind the HU - the harness I had only used one. I am assuming the other is for the dash controls.

 

Do you have a factory CD changer? There should only be one connector on the back of the factory HU. The other one might be for a CD changer.

 

nope no cd changer, I sent a msg to modifry, but its memorial weekend so I have not heard back

 

Something might have changed on the '06, but I have seen '03 and '04 HUs and there is only one connector (and the Antenna) connected to the back of the factory HU. The dash controls are in that main harness.

It is possible that Modifry includes some extra wires on his harness that a "standard" honda harness does not have (to mate up to the harness.)

You could always compare the harness to your existing one before you get started.

 

I think that is what I will have to do, it may be something new on 06 I think my 01 only had one harness as well.

 

I think the car is pre-wired for a CD changer. IIRC when I installed my Ice Link iPod adapter I had to disconnect a wiring harness which was already plugged into the CD changer port.

 

My 05 had a second wiring harness also... it's currently disconnected after installing the 9857 and DCI... would be nice to know what it was for.

 

I believe the 2nd harness is for the factory CD changer, as someone
mentioned. The dash controls are two wires in the main radio harness.
Alas, most of the aftermarket harnesses designed to plug into the main
harness don't have these two wires, because most (all?) other hondas
don't have those controls. They do have a few extra wires for functions
not used in the S2000, so it is possible to move a pin from one location
in the aftermarket harness to another. I did this when I installed a DCI
after previously installing a headunit because it was easier than redoing
all the headunit/honda adapter harness connections.
http://users.rcn.com/dhintz/Michelle/Audio/audio.html has a list of the
harness pins, and the relevant ones are #3 - Dash remote and #14 - Mute.