im not sure, its in my dads truck under his seat atm, ill eventually check it.
the HU has 4 preamp outputs, but no sub preamp output so it looks like that hu is out lol
My setup, I actually had a 4 channel amp. I ran the front door speakers on the front left and right channel. Then, I bridged the rear output for my sub. It worked just fine, and saved me space of having to get a separate amp for my sub. A couple things though, since I ran two door speakers per channel, it brought the resistance to 2 ohms, make sure the amp can handle that. Second, make sure it's ok to bridge the amp. After that, just kick back and relax.
It would be better if you had a separate subwoofer output on the back of the H/U, that way you could turn the sub up or down without having to use the EQ curve to alter the bass, because that affects door speakers too. However, if you run the sub on the "rear" channel coming out of the H/U, you could also use the fader to simply increase the power to the sub, you know what I mean?
Originally, my amp was hooked up to the front and rear outputs on my H/U, because I was planning on running my far back speakers on that channel, but I decided to get the sub and wire it into that input, and it worked just fine. It takes some tweaking on the H/U and amp for that channel, but I was getting good sound. A couple days later, I pulled my H/U out and switched the rear output, which was powering the sub channel, to the sub output on the H/U. Didn't make much of a difference in the sound, but just gave me more individual control over the sub.