??Confused and angry!

It's possible the output stage(s) of the amp are blown. Check all audio wiring connections to the amp, input and output, to make sure nothing is loose or disconnected. Also, try wiring up a different sub to verify it isn't the sub that's bad.

try one at a time. if they work then try hooking them up differently. if none work, then check to see that your amp is not in protect mode. if amp is ok, then check to make sure you have your rcas connected to your amp. in other words, re-check all your wiring. if still nothing, try your amp on your friends car and vise versa.

your subwoofer is wired incorrectly to your amplifier. Figure out which ohm load of subs you have and then what ohm load options your amp is stable at. Next go to either the Crutchfield website. find their learning center. go to subwoofer wiring diagrams. or go to www.the12volt.com and find their section on it

Your amp based on what you say would have no problems whatsoever with an 8 ohm load, not even if it actually has dual 4 ohm coils and you wire them in parallel giving a 2 ohm load (don't know your particular sub).

Every good car amp has protection circuits to prevent itself or the speakers from damage from too low loads so it shouldn't be a problem even if you screw up with your calculations. A good amp should even be capable of dealing with a dead short on a channel, zero ohms, activating protection of course.

Good luck and don't worry!

wire the sub in series it will give you best bang

it is most likely a loose wire or your RCA jacks need to be replaced for proper signal processing check all of your wires for continuity.

depends if its dual 2 ohm or dual 4 ohm

I would say since your amp is a mono, wire the 3 subs in series in the box,, with only two leads going to the amp

If what you're telling me is correct you're trying to drive a stereo sub -woofer with a mono amplifier. If so, that could be a bad situation for the amp, if the voice coils are not wired together correctly. Before we go too far, I have some questions I need answered.
1. Is the MA unit an M1889i?
2. Do you have the 4 terminals of sub-woofer tied together. For example the 2 positive terminals are tied together & the 2 negative terminals are tied together?
3.How do you supply 12VDC to the amp?

While I'm waiting to hear back from you, I'll try to draw a schematic (wiring diagram) of the way it should be wired for your particular setup that I'll send to you.

sounds like they have your sub amp in mono but they put the speakers in series which totally cancels the benefit of running your amp in mono. you will probably be happier if you just hook the left speaker to left plus and minus and the right to right plus and minus. Cuz even though subs aren't directional they do pass some higher frequencies that are and that dilutes the stereo effect.