Give me everything you know about the Fosgate sub you installed please - size – ohm – max wattage – RMS, ETC. The speaker signal is back there and you can tap your LOC in by the sub in the back. Either way you are going to need to get some extra 12 volt power back there to power an additional amp.
Don’t be intimidated by running a power line. These trucks just snap apart and there is plenty of room to make it all stealth. The key elements of running a designated amp line are;
FUSE it! I attached mine at the factory junction block by the number one cylinder, just behind the alternator. There is a big stud there (underneath the black pop-off cover) waiting for an additional wire. Run the entire line PRIOR to attaching it to the stud.
On the fire wall (as you are looking at it head on, just to the right and a little below the brake booster is a black circle that is stamped into he sound deadening material. This piece will pop out and behind that you will find a small dimple in the metal of the firewall. Drill a 1 inch hole there and insert a grommet. You can get a 1 inch grommet at any parts store in the help section for under 3 dollars. This protects the power line from chaffing and rubbing through. DO NOT skip the grommet!
(***NOTE: if you do not have any aftermarket stuff on your truck there should be plenty of room to drill this hole BUT always check BOTH sides PRIOR to drilling)
Between the junction box where you are going to make the initial connection and the firewall needs to be fused!
Continue running the line, the carpet lifts right up and the sill plates pop right off. Run it down the driver’s door sill opening under the pillar trim (you shouldn’t even need to remove it) then past the rear door sill (this one pops right off also). Tip the back seats down and finish your run. Since you have already installed an aftermarket speaker in the factory location I’m assuming you already know how to get the back panel off.
After you have the wire all the way back to the rear of the truck it’s time to make some connections. Back under the hood, remove the fuse and make your connection to the junction block. Not until the amp is completely connected will you return the inline fuse to the holder. Take some seam sealer or silicone and fill any remaining area inside the grommet, around the power line to seal back up the cabin area. You can add some split-loom to make everything under the hood look completely factory and tie-wrap any line out of the way, that may to too close to moving parts.
I think Boost ran his this way, but I’m not sure what he used for a trigger lead. You’ll need one of those or your amp will be on all the time. I connected my LOC behind the head unit and tapped into the power antenna lead for a trigger then ran everything back all together.
