ISUZU-Trooper Woofer Install


Items Used:
9/32" drill bit
12mm socket
#12x1" sheet metal screws                                   $0.99
1 roll 3/8" foam weatherstrip tape                         $2.99
1 half-sheet plywood 1/4"                                       $5.00
300 watt amp wiring kit (Wal-Mart)                       $19.99
misc nuts, bolts & washers to install speakers
Phillips & Flathead screwdrivers
         6-1/2" OZ woofers (pawn shop)                      $30.00
75x2 watt Targa amplifier (pawn shop)                 $20.00


Disconnect the battery. Remove the plate below the wiring harness entering the firewall on the driver's side. There are 2 nuts inside the truck above the brake pedal on the firewall held on by 2 12mm nuts. Once the nuts are removed, take off the brass plate. It will be stuck on with double sided foam and will take some effort. Once the plate is off, drill a 9/32 inch hole in the center to run the amp power wire through. You can use the grommet included in the kit, but you will need to drill a larger hole. I chose not to use the grommet because the wire will not be moving much. Begin feeding the power wire before replacing the plate.



I chose to feed the wire along the firewall using the zip-ties included with the amp wiring kit. Make sure you run it behind any moving parts & avoid anything hot.


Inside the truck I continued to run the power wire behind the plastic fuse panel, close to the floor. Remove the driver's side door sill (held on with 5 phillips screws) and run the power wire along the edge of the carpet. Next remove the trim piece along the outside of the driver's seat and feed the power wire under the seat. To mount the amp, I first placed the amp on the floor and using a marker, marked the hole (I only used 1 bolt to hold the amp) to be drilled on the carpet. Drill the hole, but be careful, the drill will twist up a bunch of insulation from under the carpet before drilling into the metal. I then ran the remote power wire & the RCA cables from the back of the radio, along the bottom of the center console, removing screws along the way & routing the cables over the 2 screws to keep the wires from falling out. There will be a bunch of extra length of the RCA cable, just use a zip-tie to bundle the extra into a loop. Next, attach an eye loop to the ground wire & attach it to the screw holding on the lower seat trim. Once all the wires are attached to the amp, insert the bolt through the hole in the floor. Remember to use a washer & tighten the nut. If you do any water crossing, remember to add some silicone around the nut to keep out any water.

NOTE: Remember the frame rail runs under the outer side of the drivers seat, so drill the hole closer to the center of the truck

The lid covering the compartment is held on with 3 phillips screws. After removing the screws, the lid has 2 tabs that must be broken in order to remove it. Take the lid and flip it upside down on the plywood & trace the outline. Make sure NOT to cut out the finger hole used for lifting the lid, or the cover will not be airtight. The line along the bottom (opposite of the rounded corners) can be cut straight. Place the cut piece of wood on the compartment for a test fit and while holding both tightly, flip over so the wood is down. Mark the 4 exposed holes on the wood. These will be used to hold the wood to the compartment. Measure the center of the wood horizontally & vertically. If your speakers did not come with templates (as mine didn't), you will need to make some. After measuring the bottom of the speakers (as close as I could), I used Corel Draw 9 to draw a circle & printed it on plain paper. I cut out the circle & used the paper (not the cut out circle) to measure a fit on the bottom of the speaker



Once you have the correct hole size, place the cut out circle on the wood & trace around. Then cut out the circles & drill starter holes marked on the bottom of the wood for mounting the wood to the compartment. Mark & drill the holes for mounting the speakers & mount the speakers to the board. Apply the foam weatherstrip tape along the edge of the wood. Re-install the compartment. Drill 2 holes or 1 large hole in the side of the compartment to run the speaker wires through. I used the 9/32" bit & made 1 hole & enlarged it with the bit until the wires fit.



If you want to apply Dynamat to the compartment, you can, but I tried it without & have no rattles. Attach the wires to the speakers and flip the board over. Use the #12x1" sheet metal screws in the 4 holes previously drilled to mount the board into the compartment. Do not overtighten the screws, or you will strip out the plastic liner holding them in. Cover the speakers with the carpet. You can hold it down with velcro if you want, but it is under the seats & isn't really going anywhere.



The last step is to tighten the foot located on the bottom of the passenger side rear seat. You only need to tighten the inner-most foot. Loosen the nut with a pair of pliers or a wrench all the way to the bottom of the foot. Then tighten the foot until it is as close to the seat as possible. The seat will lock back down, but it will take a little more effort than before, but you won't have to slam it down. Remember to reconnect the battery.

Thanks to for this detailed article!
Last updated on 12/17/2001 07:25 PM