Oops, didn't look at that. lol
Anyways, I'm assuming this was professionally installed? If not, it doesn't matter. You didn't tell us alot about your system, so it's kind of difficult to understand quite what your setup is.
Going by combined info in your post and your sig.... the
***umption is that you
used to have a Kicker kx600.1 to run subs, but now you have an Eclipse amp for front stage, no subs currently, and are adding a 2nd Eclipse amp for your rear fill? I really don't know, I'm just guessing from the info available here.
Your EQ does in fact have a subwoofer output, something I determined by a quick Google search for this:
http://cgi.ebay.com/CLARION-EQS746-7-BAND-EQ-7-BAND-ROTARY-EQUALIZIER-CAR_W0QQitemZ300159324179QQihZ020QQcategoryZ79841QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
The fact that it has a sub level control also tells us there's a dedicated set of output for the subs. So you can bet if the sub level control knob on your EQ actually worked on the subs, then those RCAs are hooked to your sub output.
You're gonna need to pull your EQ and add 2 more pairs of RCAs, for a total of 3 pairs coming out of your EQ (Front, Rear, and Sub) to run your 3 amps. This is to maintain fade control, anyways. You could conceivably run your fronts and rears off the same outputs but that would be kinda counterproductive if you ask me, especially if you have to run at least one new set anyways. Another alternative is to pull the EQ and swap the existing RCAs from the sub outputs to the front outputs, but then you'll still need to pull the EQ and run a new set of RCAs when you get a sub amp, anyways.
Hopefully this helped, if not, I'd be happy to elaborate if you could tell me a little more about your plans or desires for your system.