when a sub is blown it usually makes a scratcy or grinding noise if you push the sub in but if its blow it realy wont make much of a sound so it sounds like your voice coil is going out you will want to get this looked at quick or it can get expensive...i had one were it was cheaper to buy a new sub rather than fix it. it can also just be it disorting from too much power. i would never go over the power limit when dealing with 3000 watts, that can get realy expensive quick
as your sub is only rated to 400w rms simply connect the sub to either a or b channel outputs you may wish to use an rca splitter before the amp to feed both left and right audio channels into a single channel on the amp. WARNING connecting both channels on the amp to the sub will overload the sub and possibly blow it up so i highly recommend not doing so.
i was not able to locate a manual but i did find some interesting information that hopefully may help,
The AudioBahn AW1000X Car Subwoofer Features: dual 4-ohm voice coils, non-pressed pulp cone, huge foam surround, frequency response 23-500 Hz, power range 50-600 watts RMS (300 watts per coil), peak power handling 1,200 watts, sensitivity 91.1 dB, top-mount depth 5-1/4" ,sealed box volume: 0.4-.95 cubic feet, ported box volume: 1.632 cubic feet.
i'd need more info but from what you've stated, sorry to break it to you but it sounds likely you've incorrectly wired you speakers and blown your amp. this will prove no doubt an expensive mistake and learning exercise.
to drop the amp load to 1 ohm you need to divide the output signal path and the best way is by wiring a second woofer in parallel as seen in the ideal diagram attached this has the desired effect of doubling the volume .
since 2 ohm divided by 2 is 1 ohm load connected to your amp.
so the short answer is no you can't do that with a single woofer
Generally there are 2 parts to this problem
input signal as these woofers are just subs remember to give them a low line in signal before the amp (see diagram) i like to use rca low pass crossover filters from harrison labs (see link)
is the wiring configuration of the 2 woofers by wiring them in parallel as shown in the diagram you reduce them to a 2 ohm load for your 2 ohm amp meaning you'll get max loudness and efficiency
Harrison Labs FMOD Inline Crossover Pair 100 Hz Low Pass RCA Shipping is...
unfortunately if you only have the one woofer there isn't really any safe way to do so but if you had a pair of woofers you could in theory wire them in parallel thus creating only a 3 ohm load but your amp must be able to work at such low ohms otherwise you WILL blow up your amp.