Verifying line output converter

Hi, I'm trying to troubleshoot my amplifier installation - my old amp was a rockford fosgate 550s, but the wires going to the subs shorted out, and the amp stopped working. I put my new amp in but didn't hear any sound. I tried measuring the output of my line output converter with a multimeter, but it read 0 volts. I had it in AC mode but there were only two voltage options, 200vac and 500vac. I put it in 200vac mode but I'm not sure if 4 or 5v will even show up then - anyone know? As an aside, I have a pioneer DEH-8500MP (the line output converter is left over from when I had my stock HU). I remember it being a pain to get out of the car before - the audio shop had to use some special tool. I want to hook up RCA cables to the sub output of it, so I can skip the LOC altogether, but I'm not sure if I'll be able to do that without the special tool. I would check but before I disassemble the center console / dash area I'd like to know it won't be a complete waste of time to attempt to reach the back of the HU (this is in a 1999 Acura TL btw). thanks for any input!

Forgot to add, I even checked the levels at the RCA outputs of the LOC while my HU was playing a test tone. I just made a quick 220hz tone at full volume (after reading the forums it looks like I should have used a 1khz tone, but I don't think it should matter too much) that is a minute long, then copied it onto CD 3 times so I'd have 3 mins of 220hz (also did the same thing for 80hz, probably should make it lower for a better sub test tone). Am I checking the RCA cables correctly? I putting one probe on the outer rim of the RCA connector, and the other probe on the inner prong of the connector. I thought the inner prong was positive but I tried both anyway, and neither of them showed a voltage...

first off you wont be able to measure the output because the car is DC and you had it in AC mode.  Ok your HU has 3 pre-outs built in so you do not need the LOC's you will plug your RCA's direct into your HU.  Now that I read your post again I believe you are asking about pulling the stereo itself out of your dash.  I am not sure of needing any special tools to take your dash apart besides maybe a panel popper which is basically kinda like a bent screwdriver.  I am not to sure about your specific vehicle, but the only thing I could think of needing a special tools to get the stock HU out would be something like DIN removal tools for FORDS or something like that.  I honestly do not think but please dont quote me that you need any "special" as u said tools to remove your HU.  What exactly are you trying to do?  There may be a way around all this fuss.