Thanks to Vaboom's audio install guide, I figured out how to remove the stereo. I'm planning to install a 4-channel LOC there and didn't want to cut up the existing wiring.
I found on the protege forums a wire harness from Metra that works with the 3 with a few modifications.
The part numbers are here:
71-7903 (into stock hu)
70-7903 (into car harness)
It does require a bit of modification though, some of the pins are in alternate places, if you plan to do the same as me you'll need 2x 70-7903 and 1x 71-7903. Its because the 70-7903 doesn't have enough wires to simply move into other places like on the 71-7903, so you'll have to buy 2 to have enough wires to rearrange. Anyway I've done the mod to the 71-7903 so that its exactly as the 3.
Here's pics:
you can see the connector itself is the same, however a few wires are in different places.
to get out the wires you have to pry the cover from the connector (yellow arrows) at the same time prying up (top green arrow). The bottom green arrow is a second latch when you're pulling the wire out, see below for actually pulling the wire.
heres the cover off
now here's where you pull the wire, you have to move the little white holder out of the way (green circle+arrow) then pull down on the wire. It'll stop half way where I mentioned above (second latch) you have to pry it up (it doesn't come out all the way) and then pull the wire the rest of the way down. However sometimes if you pull really hard it'll just come straight out.
to put the wires back in just shove real hard until it reaches the top and snap the white cover back in place, then you're done.
My camera ran outta batteries, so I don't have pics of the other side of the harness. I'll post that up tomorrow night.
I found on the protege forums a wire harness from Metra that works with the 3 with a few modifications.
The part numbers are here:
71-7903 (into stock hu)
70-7903 (into car harness)
It does require a bit of modification though, some of the pins are in alternate places, if you plan to do the same as me you'll need 2x 70-7903 and 1x 71-7903. Its because the 70-7903 doesn't have enough wires to simply move into other places like on the 71-7903, so you'll have to buy 2 to have enough wires to rearrange. Anyway I've done the mod to the 71-7903 so that its exactly as the 3.
Here's pics:

you can see the connector itself is the same, however a few wires are in different places.

to get out the wires you have to pry the cover from the connector (yellow arrows) at the same time prying up (top green arrow). The bottom green arrow is a second latch when you're pulling the wire out, see below for actually pulling the wire.


heres the cover off

now here's where you pull the wire, you have to move the little white holder out of the way (green circle+arrow) then pull down on the wire. It'll stop half way where I mentioned above (second latch) you have to pry it up (it doesn't come out all the way) and then pull the wire the rest of the way down. However sometimes if you pull really hard it'll just come straight out.

to put the wires back in just shove real hard until it reaches the top and snap the white cover back in place, then you're done.
My camera ran outta batteries, so I don't have pics of the other side of the harness. I'll post that up tomorrow night.