When my RCAs are hooked up to my amp, my subs start hitting without any volume turned on

You will need one pair of RCAs connected to the unit in the rear where it says "sub" and a remote turn (connected to the radios blue and white wire) on running from the radio(with the RCAs) to an amplifier. You will also need a power cable from the battery and a chassis ground coonected to the amp. Connect the subs (usually in some sort of enclosure) to the amp.

It sounds like your amp has lost a channel, based on the testing you have done so far.

Have you tried your subs on another amp???? Or hook up a small speaker at low volume to the amp and see if it plays....If it doesnt, then the problem lies within your speaker output on your amp or your line out (rcas) on your stereo

1. Check Grounding system (Player and Power Amp).
2. Ensure your RCA cable is OK
3. You might adjust volume or bass volume on power amp to maximum, just set all to 50% while you are tuning.
4. Check the speaker out cables might contact the ground/ chassis

how to power on the amp on my flip out headunit

they want you to "level match" the amps head units voltage from the rcas .this is best done with the radio at 3/4 volume , turning the amps gain dial till music distorts then backing off till it sound s clear .if theres other units in the signal chain (eq,x overs, ) see if they too have gain /volume controls . it goes down the line if thats the case . .

If you power up the amp with the RCAs plugged in, does it go into protection mode.

If you power up the amp with the RCAs plugged in, does the woofer pop?

I'm not that familiar with the insignia line but If the amps have an "input" and an "output" for the RCAs then run the RCAs in one, Then hook the output of that one to the input of the other. I did this with my 2 memphis 500Ds and it worked great. It also looks better than a couple of splitters, but yes You would just get two splitters with all female connections on them so you can plug 2 sets of RCAs into the one set. Also it doesn't really matter how you hook the RCAs up unless you are going for stereo sound then you would need to make sure the rights are hooked up together and the lefts are hooked up together. I hope I could help.
-Andrew Hawkins

either the rcas arent outputting the audio signal or you have a bad se tof rcas. An amp is obiously not your issue in this case.

There are a couple of tests you can perform. I'd first recommend checking the shield ground. You'll need an ohm meter. The details can be found on the following page.

RCA shield ground test

You can also test the output with the multimeter. Set the multimeter to AC volts. If it's not an auto-ranging meter, set it to a voltage range of ~2v AC. Disconnect the RCA cables from the head unit. Touch one meter probe to the outer ring of the head unit's RCA jack. Touch the other probe to the metal contact in the center of the RCA jack. With the head unit near full volume and a clean signal source, you should read at least one volt on musical peaks. If you have a bass disc or a test tone disc (~60hz sine wave), use those.