Evrything hookup there is no sound iget a good signal in the back of the sub so whats the problem

Check for a bad earth on the brake light as if the power can't get to earth normally it will back earth through any associated wire and turn that bulb off.

Mine has issue with the sub input that runs from the receiver sub output. So I don't have the LFE effect. I have to use the secondary hookup which is:
-run your front speaker wires from the receiver into the input. Then run wires out back to your front speakers.
Is your completely dead period? Or is the light coming on? If its dead, it may be a fuse or the power supply has failed....if the light comes on. Try the secondary hookup. Make sure both your reciever and the sub are unplugged. Plug them back in after you have hooked everything up..

Sounds like you have no signal going to the amp. Check th RCAs.

First of all Id like to state that Reality car amps arent the best quality amps on the market and they normally will burn out on you. From what you are telling me it looks like your sub outs are defective, the output signal from the car amplifier is dead usually due to weak or defective terminals or poor soldering by the manufacturer, very common with lower quality amps. My suggestion is to replace the amp with at least a mid grade amp like a sony xplod or pioneer amp , if money is an issue then you can have the outputs checked out , check the wiring and also make sure that your ground is solid and making good contact to the cars chassis otherwise you wont get sound. Check the Amp turn on cable which is the small blue wire and check that your radio has the amp turn on or subwoofer signal turned on. Let me know your status and Ill do my best to help you out.

Good luck,
Lex.

wrap a striped speaker wire around the back of the rca out put on your cd player and for the record that aint a 2300 watt amp its like a 300 watt amp

this is caused by inproper wiring from the speakers/subs to the amplifier.. an amp will still put out power to subs and speakers when it's wired improperly but it won't last for very long doing it... 6 months is longer than usual....

your audio wires from the head unit have been pinched or discontected or the head unit is not putting out a signal

THIS UNIT HAS NO SUB WOOFER AMP IN IT. THE ONLY WAY TO OVER COME THIS IS TO HOOK THE LEFT AND RIGHT FRONT SPEAKERS STRAIGHT TO THE SUB WOOFER AND THEN GO FROM THE SUB WOOFER BACK TO THE INPUTS ON THE BACK OF THE UNIT FOR THE FRONT SPEAKERS. THE SUB WOOFER THIS WAY WILL EXTRACT THE BASS AND THE FRONT WILL RECEIVE THEIR PART. THIS SOUNDS CRAZY AS HELL I KNOW BUT THAT'S HOW I GOT MINE TO WORK. THE OUTPUT FOR THE SUBWOOFER IS USELESS AND PUT THERE FOR YOU TO HOOK UP AN AMP FOR A SUB WOOFER. EVERYTHING HAS SHORT COMINGS, AND THAT'S THE ONE FOR THE AX-720.

good day, check your spkr impedance, if 4oms use a posive spkr dividing network. if stills blows up replace a higher amperage of your fuse. ex.4A raise it up to 5A. the your amps consume higier current if more spkr wattage.

I have the same problem. My guess is that the subwoofer coil is messed up. You MIGHT have to get it recoiled. But before you do any of that get someone with a sub to play their sub in your car, if it works.... then your sub is messed up, if not.....then your amp is messed up ( trial and error ). Today i noticed my subs rubber surrounding is crooked, that may be the problem for me. Also when I press down on the sub it makes a sticking sound, like something came loose. So once i get everything opened and out ill let you all know the solution. Good Luck!