Price: $135
Time: 4 hours
Tools: Wire cutter/stripper/crimper, wrench, screwdriver, razor, electrical tape.
Parts: Pyramid PB440 amp, Jensen XS1011Bp sub, 8 guage power wire, 16 guage speaker wire, dual-shielded RCA cable with remote turn-on wire, gold plated RCA connectors, inline fuse holder and fuse, red 3M Quick Connectors, crimp terminals, zipties. You can get this stuff cheap from Parts Express.
1. The first and most difficult step is to run the power wire from your battery to under the passenger seat. Usually you drill a hole through the firewall to get to the engine bay, but the Focus has an unused rubber grommet near the wires that go to the driver's side door, pictured below. Unscrew and pull off the bottom kickpanel and floor trim to expose the wiring underneath. Pop off the fuse panel cover. Pull out the corner of the padding in there and you should be able to see to the back of the grommet way back in there. Slice a hole in the grommet with a razor and force the wire through, it's easier to do from the outside and then grab and pull through from the inside.
2. Pull most of the wire to the inside of the car, and then feed it through the top of the fender. Open the hood and pull the wire through just behind the hood's hinge. You can then run it up to the battery as illustrated below.
3. Pull up the carpeting under the driver's pedals and run the wire next to the edge of the floor padding. Send it underneath the center of the dash to the passenger footwell.
4. Remove the center console (2 screws under the cupholders, one in the rear, and two that hold on the armrest, under the plastic piece just behind the armrest). Unscrew the two hex bolts and pop off the plastic covering the bottom center of the dash (in front of the cup holders). Feed the wire from behind through the inside of the metal bracket, under the rear heat duct, and into the console area.
5. Run the wire along the inside of the right rear heating duct. Do the same with the RCA cable(s) coming from the head unit. Ziptie them in place near the shifter so they do not interfere with it. Run the wires out under the duct just before the duct vent.
6. Cut a short ground wire and crimp a terminal on the end. Connect it under one of the many screws in the floor of the console. These were all very tight and I was finally able to get the one under the armrest loose. Screw on the connector and run the wire out under the heat vent.
7. Make sure the end of your power wire isn't in contact with anything...tape off the end. If you have a voltmeter, test to see if there is a voltage between the positive terminal and the end of the power wire; if there is, the insulation may have worn off somewhere and it is touching ground...hooking this up will short out the battery and may be very harmful to you and your car!! Assuming all is fine, attach the inline fuse holder to the end of the power wire (I used a twist-on wire connector), crimp on a terminal, and insert a fuse. I recommend sealing all connections with electrical tape. Unscrew the screw holding on the positive wires (this too was very tight, I had to use a small amount of WD40 applied with the tip of a screwdriver) and attach the terminal.
8. Back under the passenger seat (moving it all the way forward and working from the back seat is easiest), cut all wires to length and attach them to the amp. Don't forget the remote turn-on wire from your head unit or switch! Because the carpeting is almost an inch thick under the seat, I simply poked the amp's screws through the carpet, they will keep it from sliding around but can be easily removed. Run wires to your speakers (that's a project in itself) and you're done!
