low volume from sub

First off I wanted to thank the "powers that be" for the useful info on the site. It helped me to properly install the ground and the big 3. I recently purchased and installed a Hifonics BXi2008 to replace an old amp I had in my 96 Chevy Van. I just finished the install and powered up the system tonight. The problem is the sub(Clarion SR1045 4ohm, 325watts RMS) has very low output, the only way to tell if its playing is to touch the surround. The head unit(Sony CD 805GTX) volume was at about 65%. The head unit is set flat, all boosts are off/zero. When I adjust the level on the BXi2008 from 9v to .2v there is a minimal increase in volume(Head unit @ 50%). When the bass boost control is changed from min to maxx there is no change in volume(Head unit @ 50%). I checked the troubleshooting section of the Hifonics manual and what they listed are within specs. The system voltage at amplifier with system on is 14.2 volts. Ground resistance is 0.7ohms. Power cable is 10' long 1/0AWG with 200 amp fuse and the ground cable is 1AWG with 20" length to lug in chassis. Another 1AWG cable goes from chassis to neg post on battery. I have swapped out the existing RCA cable but that did not make a difference. I suspect that the amp is defective or the preamp for the sub outputs in the head unit is defective. Anyone else have any suspicions on what it might be?

Did you notice that the terminals of the amp are + + - -? They are not the traditional + - + -. You may have the speaker connected to the 2 positive terminals. When you touch the surround, you are feeling the speakers reaction to the bass coming from your top end speakers.

Thanks for your response. I have the first plus and the first minus connected as per the manual for a single VC - single speaker install. So connector position 1 and 3 are in use. ie Con + Con -

I had a similar problem once and it turned out that I had connected the RCA's to the wrong set coming out of the HU, (there are 3 on my PYLE HU)  just a thought

My rear speakers/amp work fine so I tested the amp with the RCA's for the rear speaker amp and had the same issue. I talked with Maxxsonic and they said the Amp has an issue. Thanks for the help