I bought the Scosche GM-035 wiring harness, the one for the 2000 Tracker that everyone here says works perfectly except you lose your chimes. So I thought it would be just a matter of clicking one end of the wiring harness into my car and clicking the other end into the HU and voila, but no, although it did plug into my car, the other end of the wiring harness does not plug into my new head unit, instead I had to connect about 10 wires manually from my HU to the wiring harness. So I connected them all by matching the colors, but the head unit has about 4 wires less than the wiring harness so they remain unconnected to anything. Anyways, the HU will not power up. What am I doing wrong?

your missing your ignition wire....do what most people do and tap in to your wiper fuse, or do what i did and go to the ignition harness....thats the red wire on the HU by the way. Or for now you could put the yellow and the red together but the radio will always be on....dont worry about the other wires as long as you got your power wires and your speakers your good to go

Sorry for the newbie question but what exactly is a wiper fuse and what do you mean by tap in to it?

Should the red wire from the HU not be connected to the red wire on the wiring harness?

It doesn't work! Connecting the red wire from the head unit to the yellow wire on teh wiring harness results in nothign happening. Help!

Ok I found a diagram on the internet which explains what each wire from the head unit is for:

front left speaker positive - white
front left speaker negative - white/black

front right speaker positive - grey
front right speaker negative - grey/black

back left speaker positive - green
back left speaker negative - green/black

back right speaker positive - purple
back right speaker negative - purple/black

So I just connect those 8 wires to wires of the same color on the wiring harness, correct?

Then there is the black ground wire which I connect to a screw connected to metal.

Then there are the yellow and red wires which are the constant and switched power source. Now what I don't understand is, why can't I just connect those red and yellow wires to the red and yellow wires on the wiring harness? And if not, then will the red/yellow wires on the wiring harness remain unconnected to anything?

I assume the yellow wire powers the clock on the head unit, while the red wires powers the rest of the unit.

Well our cars dont have a true switched power behind the radio, so you must get it from some where else. The wiper fuse is on the side where the fuses are (side of dash when you open the driver door). You can run a wire from there to the radio and connect that to the red wire. If putting the red wire from the radio to the yellow wire doesnt work then your ground is bad or you got no power...Also the radio could be fired which i doubt is the problem here. The yellow wire is actually constant or the "memory" wire the red wire actually turns the system on when it see power. Yes just connect every thing to the harness you just have to get the power for the red wire from the wiper fuse. dont connect orange wires and make sure you tape em up

Ok thanks a lot for the info I'll try that today.

Straight from my sticky -

2000-2005 Cavalier/Sunfire owners -

Confused on which harness to get? Don't want to spend high dollars on an install? Do yourself a favor and get a wiring harness for a 2000 Geo Tracker or a Chevy Trailblazer. Get yourself an add-a-circuit as well - you can get them at your local auto parts store. Get the one with the small fuse, not the bigger fuses.

Wire your harness as you normally would but one exception - the red wire - the switched 12 volt wire - you're not going to wire into the harness. Instead, crack open that add-a-circuit and get the 10 amp fuse. Put the 10 amp fuse in, unplug your winshield wiper fuse, and put the add-a-circuit into the wiper fuse slot. Replace the fuse into the add-a-circuit, wire up your red wire to the add-a-circuit wire (you're going to need a short piece of 18 gauge wire to do this) and voila! Your radio will work now.

Thanks that helps a lot, I'm gonna go hit up the auto parts stores and buy an add-a-circuit.

One question though: I looked at the wiper fuse and it says 25 on it, but the fuse on the back of my head unit says 10 on it. Is that ok?

yep its fine

Ok I bought a mini add-a-circuit (the damn thing was $18) and a wire to run from there to the HU, and connected all my HU's wires to wires of the same color on the wiring harness, except for the red wire which I connected to the wire from the add-a-circuit and clicked into the wiper fuse slot. The HU shows no signs of life. I know my car works fine because the wipers work, and the stock stereo works when I plug it in. What am I doing wrong? I'm thinking I might've blew something in the HU but how is that possible when it has its own 10A circuit in the back to protect it.

Scratch that, it works! Reason it wasn't working before is because I didn't hook up the antenna. I don't see why that should prevent it from turning on, but apparently with the antenna disconnected it won't even turn on. Anyways, I got it working now, thanks for your helf everybody. Next on my list are a pair of quality 6x9's because this bass sucks.

You have a bad ground wire my friend. Connect your ground to the chassis instead of where it normally goes.

To what chassis? Right now I connected the ground to the black wire on the wiring harness (which I assume is the stock ground). I could not find anything metal to connect the ground wire to, everything nearby is plastic.

You might have to run a longer wire, but back behind the dash and underneath where that plastic piece is by the shifter is metal. Try grounding to it. Right now it's using your antenna wire as your ground. Electricity uses the path of least resistance, and right now, that's your antenna wire.

Ah so THAT's why it didn't work until I connected the antenna... Well at least it's grounded... I don't want to run a long wire because it's too much work. Maybe next spring when it warms up.