Bad screw in terminal strip for speaker

contact the company and get a list of authorized repair agents close to your location
if there are none and it is out of warranty then find an accredited electronic repair shop and ask around to see if they have experience in your brand of unit

It has two speaker terminals which allows you to wire muliple subs to the amp easier than trying to cram the wires all into one set of terminals. The two sets of terminals are wire in parallel internally on the amp, so it matters no which + or - you use on it. However, you need to remember they are already wired in parallel internally, so if you were to wire up two 2 ohm subs, the amp would see a 1 ohm load (which it's not stable at), not a 2 ohm.

RF uses some pretty funky cases in order to hide the wiring.

usually a screw or 2 on the top will allow its removal and expose the wiring terminals

Wire it in a series. One wire from amp positive to one positive speaker terminal. One wire from amp negative to negative speaker terminal. This should leave one positive and one negative termianl on the sub. Use one additonal wire to connect these two, this wire should not be connected to anything else other than the two remaining terminals. This will allow you to have the music up louder with higher amp settings without having to worry about blowing the speaker as easily.

if you have one that you can compare to another, go to home depot with that and match it up. If not, take the amp to home depot and get someone to help you find the right one.

Check you inputs to verify you have a signal coming in, if signal then check outputs try a speaker that you know is working and plug it in if that speaker plays then the subs/ or speaker wiring is bad, if it doens't play then you probably have a blown output transistor on the amp or possibly a terminal ground/positive has come loose on the inside..

Disconnect the speaker wires from speaker terminals on the amp and turn the amp on (turn the head unit on). Set the volume to zero on the head unit.

Does the amp get hot?

If it does, either the bias is set to high or the amp has other problems. If it does not, you may have the speakers wired to the wrong ohm load.

There is no reset button. If you disconnect all of the speaker wires from the amplifier's speaker terminals and unplug the RCA cables, does the protect light still come on (I assume that you've already replaced the fuse)?

If you're talking about the amplifier's power terminals, the positive terminal is designed to be wired directly to the battery (be sure to fuse the amp power wire near the battery terminal). The negative terminal should be bolted to vehicle chassis metal for a ground connection. The only amplifier connections that go to the back of the head unit are the remote turn-on wire and the RCA cables.