Tachometer Install Problem

Hey, I currently have a 93 Honda Civic DX. I just got it a few days ago and all i've done so far at the shop is put 2 1/2" in piping from the headers back and add a small muffler for a nice sound.

The problem I'm having is the DX didn't seem to come with a tach, so I bought an aftermarket one and installed it. There are 4 wires, black, red, green, and white. I put the black one onto a piece of metal to ground it. Red I attached to the red wire on my deck so it has power. Then I opened up the dash cluster and attached the green wire to the "blue" wire? I don't know if that's right, but it was the only wire that seemed to work. Now the tach works and all, but my problem is it won't light up when I turn on my lights. I attached my white wire to the light fade switch like it said in the manual, but there's 3 wires there. 2 red and 1 black. If i connect the white wire to either of the red, the tach doesn't work, but when I connect it to the black, everything works fine, but it just wont light up. Any ideas what I'm doing wrong?
Edit/Delete Message

The black wire should be a ground for the dimmer switch, so don't use that. You could just try connecting the white wire to the same one as the Red (the deck power) and it will work but the light will be on all the time. That's probably the easiest way to get it to work for sure (also what I did with mine), but that's weird that it didn't work with the one of the red wires in the back of the dimmer switch. But the blue wire is right for the tach signal.

ok, thnx for the info, I'll go try that :)

Dash lighting is a red wire with black either dots or a solid stripe, I can't remember which but I have mine hooked up, and it turns the tack light on and off with the dash lighting no problem, it just won't dim with the dash lighting, but that's fine with me.