Metra harness and mach 460?

I believe I have found out why my car's sounds system sounds like ass. It appears the previous owner bypassed the factory amps and ran new wires from the new head unit to all of the speakers. The sound is rather "tinny" with a complete lack of deep bass and distortion at higher volumes.

My question is to those who have used a metra harness (I believe I need the 70-5510), how do you like it?

I'm questioning what is happening to the signals coming from the head unit really. It's my understanding the amps need a low level line to operate properly...so does the RCA's feed the amps all of the signals which then gets re-distributed to the correct speakers?

Yep, I just found out the second set of rca pre-amps are switchable to rear or sub. With that said, I'm now wondering if I can't just take a set of cheap RCA's that I already have, cut them in half and splice into the wires that area already there. I could then disconnect all of the speaker wires, reconnect the amp's to the speakers (I'm assuming they left the amp wires running to the speakers), plug the rca's into the head unit and leave everything else connected as-is? I mean, the lines running from the small connector should already be low level line inputs to the amps…right?

I've converted RCA cables over for use as a shielded ignition cable without too much fuss. He left a chopped off adaptor/connector in the glove box for the small 8 pin which is labeled for both front +/- and rear which I believe is the connector for the low level line to the amps. Really, it's only a matter of soldering/shrink-wrapping the RCA's to the connector, disconnecting the headunit speaker wires and capping them…and then plugging everything back in. I think I may give it a shot…and the only thing I'll be out if it doesn't work will be a cheap set of RCA cables which I likely will never use again anyways (damn I love HDMI cables).

For sure though…first things first is to make SURE the stock harness is still intact!

Ok, I've got an update. I pulled the head unit (pain in the arce) and found indeed he wired everything separately from the head unit! The fact that he had the black 8-pin connector with bare wires tucked in the glove box looks like he tried to use it and couldn't figure things quite out. He also has a set of rca's from the head unit's rear/sub going to the trunk. I'm thinking he hooked up a sub to compensate for the lack of bass coming from the head unit.

For tomorrow I'll have to find out if the stock wires are still hooked up to the factory amps and if not...I'll have to reconnect them an remove the new wires. I'm going to skip the metra harness and stick with my plan of chopping up some spare RCA's and hooking them to the 8-pin connector I found...in essence creating my own adaptor.

On a side note, is there a way I can tell if the stock amps are functional before I go through all of this?

Ok, he clipped the friggen wires in the doors/panels and bridged both woofers and tweeters together. No wonder it sounded like ass.

Anyways, with everything hooked up it seems the right rear amp is producing a buzz and not putting out anything to the rear woofers. I could wiggle the rear plug and get the buzz to go away, but it doesn't make the woofers work. I simply disconnected the plug going to the amp and the buzz went away (but again, no rear woofers). These should have 3 wires for the rear amp plugs, correct?

More good news, the left rear tweeter is blown completely while the right rear tweet is working as are the front woofs and tweets. Even with all of this chaos going on, this setup sounds WORLDS better than having 4 channels from the head unit feeding all 8 speakers! Seriously, everything is more crisp and I have a ton more base (without the rear woofers even working!)!

On a side note, while pulling apart the Shi#$% wires (which were simply twisted and taped)and solder/shrink-wrapping, I noticed there were some wires from the factory harness not being used. The first being a Black wire (connected to orange/black stereo wire which was clipped), the second being a Blue/Red wire (connected to orange/white stereo wire which was clipped) and a black wire which is taped to another wire with some sort of single clip on it. Does this sound right?