Boy am I confused! So much for a degree in electrical engineering....

I have in front of me the wiring harness for my Pioneer (DEH-P80MP), Modifrys DCI, and the Honda wiring harness adapter (the one from Modifry with the extra wires, I have almost the same thing from Crutchfield but missing the controller wires). I am connecting things like mad and doing great, then I run into the Dimmer/Illumination wires.

Pioneer: An orange/White wire marked ILL (the instruction manual talks about a dimmer....)

Honda Harness: An orange wire and an orange/white wire. According to the Crutchfield doc the orange wire is "illumination" and the orange/white wire is "Dimmer"

Which to hook up? I started by soldering the Honda harness orange to the Pioneer orange/white because they both said 'Illumination". Then, I decided that can't be right switched to orange/white and orange/white. Seems right, but names don't match. Hmmm, better search the web to be sure.

Ackkkkk - I found appends on various forums that said to use each one! Tried search here and even found one append that said not to connect to either one. I found a useful append that said that the Illumination wire indicates whether the headlights are on or not. That sounds right, but...

So which one do I connect to my Pioneer?

 

The one marked illumination worked with my Alpine head unit.

They may both work. I am thinking that the dimmer wire is an analog signal related to the brightness of the dashboard lighting, while the illumination wire is on/off.

If that's true, it's possible that if you had your lights on and dimmed the dash lights too much, the headunit display would switch to full brightness. In other words, the dash lights could dim below the threshold that the head unit uses to decide that the lights are off, and it should be at daytime brightness.

Hypothetically, at least. I didn't experiment with it when I did the installation, or even check whether there was a wire there in the car's stereo connector.

I'm looking at the manual now. Is the dimmer wire located between right front speaker (-) and ground? It looks like that wire is tapped off of the backlight for the dashboard audio controls, so it would be an analog brightness (dimness) signal.

My Alpine head unit only has two brightness levels, day and night, so the on/off illumination wire works fine for me.

 

I think that I will switch it back to the (orange) illumination wire like I had it originally -- I found appends in other Honda forums talking about damage to the dash circuits when the dimmer wire is hooked up and I sure don't want to do that!

 

I left the orange/white loose (but taped up) on the car side of the harness, and connected the solid-orange wire to the 'illum' wire on my alpine harness.

 

Yea dont connect the orange wires. I used to install at circuit city. Also, circuit city sells quick connect harnesses. I bought these for my s2k, and i actually have the same pioneer headunit that you have. They just clip together, there is no stripping, soldering, taping required. Just thought i would add my 2 cents.

 

i'm confused too cause my deck has orange / white and of course the harness has both.

 

Thanks, everyone.

I did not know that you could get a no-solder harness, but on the other hand I am using Modifry's harness with the two extra wires for the dash controls and would have ended up doing some soldering anyway. Its no big deal and I can be sure that I have proper connections this way. I used shrink tubing for insulation and except that its a big tangle of wires and things it looks pretty good.

I did end up connecting the orange Illumination wire from the Honda harness to the orange/white Illumination wire from the Pioneer wiring harness. That matches what people are saying here. I also found an append somewhere that said that dimmer systems vary - so most HU manufacturers provide their own dimming system based on the Illumination signal. I will try it tomorrow because its getting dark and its pretty cold here (Poughkeepsie, NY).

I had no trouble pulling up the center console with my fingers, but the radio fascia does not seem to come out as easily and I am a bit afraid of breaking it by just pulling on the door as one discussion suggested. I will instead tape up something flat and pry it out like it says on the Lucid site.

 

tape up your radio door too or you''l scratch it. I got a nice one now.

it's the orange wire. I used my testlight and orange/white had no signal while orange had some output.

my deck is done. now to move on the the rest.

 

I did tape everything and my install went great (although I spent a long time trying to fish something through to pull my speaker wires, and even longer cutting the stock speaker baskets).

For the record in case anyone ever asks this question -- the orange Illumination wire in the Honda harness is definitely the right one for the orange/white Illum wire from the Pioneer.

 

Thanks goodness for search!

I just went through the same confusion with my Modifry harness and Alpine unit (Modifry harness has both Orange "ILLUM" and Orange/white "DIMMER", while unit harness has ORANGE "ILLUM"). I figured orange-orange ILLUM-ILLUM made sense, but it's nice to get confirmation.