i tried using the direct no LOC connection, however on this amp it is simply a RCA connector on one end and the other is simply wires you connect to the factory speaker for signal, this did not work out well either.
I also have the standard 6 speaker system. I will try and verify which speakers i am currently tapped into but I'm pretty sure its the fronts.
Also just for more information my impala also has a battery in the trunk, behind small panel on drives side trunk, however this is only to ru the basic systems while the car "shuts off" during idling. i wouldn't connect it to an amp as you always risk the amp potentially draining that small battery during idle which in turn could one day ruin it for good.
Mine is ran directly to the battery.
You must have the 4 cylinder. Mine's a 6. No battery in the trunk, just the factory (although labeled Bose) amp, behind the trunk liner on the passenger side. Sorry about that...
Either way, good plan not using your trunk battery on that one.
The wires I tapped into were in the "bottom" 8-pin connector on the amp- right front: yellow=positive, yellow/black=negative
left front: blue=positive, brown/blue=negative
IF those wires don't correspond, the easiest way to find out would be by looking in the rubber "boot" that runs from the front door pillar into the front door. On the door side should be smallish (smaller than the body side) rectangular piece. If you gently push that into the door, the groove that holds the piece will come loose. You can then kinda fold or squish it to pull it out of the door. Once you do, you should be able to see the wires that the boot is protecting. That's how I confirmed which wires went where on mine. The speaker wires should be easy to recognize, since they are a heavier gauge wire, and are twisted together.
To put the boot back, just push the "inside lip" back into the door. Might take a bit of wiggling, but it will go. Just give the boot a pull to see if it is seated all the way...
As for why you aren't getting any signal to your subs, I hate to ask a stupid question, but do you have your LOC hooked up to the battery with a 1amp fuse as well, and properly grounded? (there are very handy grounding points on the inside of each fender) You shouldn't need the "main" output nor control settings, so I'd leave them alone. Is the fuse on the amp or by the positive battery connection still good?
Not sure what else to say without knowing the exact amp and sub set-up you are using.
(Wizetek posted at the same time. Good info there too!)