Multiple amp's to stock stereo?

[jessdabest77]

I have a 2008 Chevy Avalanche and trying to install two amp's to the stock stereo using a Clarion eq(pre-amp).One amp is a 4 channel and the other is a mono block for my sub's.I have installed a hi/low converter,ran to the main output of the eq,but the problem is, only the front channel come's on,and not the rear or sub's.I have tried running each amp without the eq to the hi/low, and it each amp worked,but not with the eq.I thought it was my hi/low,so I bought a new one,and same problem.So,then I thought it was my eq,so I bought a new one ,and nothing,same problem.I'm super stumped here guy's.I have installed eq's on factory stereo's before,but never had this problem.If anyone can help,thank you so much.

[NorseDevil]

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[conceptM]

Is the EQ powering up?

Is the Eq splitting up signals (High pass - Low pass)?

Have you tried connecting the high low convertor to the amp directly?