Wiring Subwoofers and Amplifiers to the Trunk in a 1st-Gen Acura CL
Introduction
This guide covers routing amplifier and subwoofer wiring from a dash-mounted head unit back to the trunk of a first-generation Acura CL (1997-1999, both the 2.3 four-cylinder and 3.0 V6 models), and mounting the amplifiers behind the rear seats. It is aimed at a typical build with an aftermarket head unit already fitted, a subwoofer enclosure, and separate amplifiers for the subs and the rear 6x9 speakers. The work involves getting a heavy power lead from the battery into the cabin, carrying it and the signal cables rearward without drilling unnecessary holes, and delivering everything cleanly to the trunk. Two routing methods are described — a permanent path under the seats and door sill, and a quick coat-hanger fishing technique — so you can choose whichever suits your car. Adapted from a community writeup by Ecct on AcuraZine (https://acurazine.com/forums/1g-cl-diy-faq-74/diy-request-how-run-wires-headunit-subs-trunk-482929/), including corrections from the follow-up discussion.
Reference
Tools Required
- Wire coat hanger or fish tape
- Trim/clip removal tool or flat-blade screwdriver
- Socket or wrench set for the battery terminal
- Wire strippers and crimping tool
- Electrical tape
- Drill (only if you choose not to reuse the firewall grommet)
Parts Required
-
Amplifier power lead with inline fuse holder (gauge sized to amp draw)
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RCA signal cables
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Amplifier remote turn-on wire
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Amplifier ground wire
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Subwoofers and enclosure
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Amplifier(s) for the subs and 6x9 speakers
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Speaker wire
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Sound-deadening mat (optional)
Safety Warnings
- ⚠ Disconnect the battery's negative terminal before routing the power lead, and keep its ends taped until the amp connections are complete.
- ⚠ Fit the inline fuse on the power wire within a short distance of the battery so a short to chassis cannot ignite the lead.
- ⚠ Where the power wire passes through any metal panel, protect it with a grommet or loom to prevent chafing and a dead short.
Step-by-Step Instructions
1 Open the rear trim for trunk access
Reach the boundary between the cabin and the trunk by releasing the rear side trim panel beside the back seat; on the first-gen CL this panel is held by clips and unsnaps by hand. This exposes the route the wiring will follow into the trunk area. Pulling the rear seat cushion is one option, but as several builders in the discussion pointed out it is usually unnecessary — the cables can be fed without removing the seat.
2 Pass the power lead through the firewall
Bring the amplifier's main power lead from the battery into the cabin using the existing rubber grommet where the factory harness enters the firewall. Work the grommet loose from the cabin side, feed the new wire alongside the bundle already routed there, and reseat it. Reusing this opening avoids drilling a fresh hole and keeps the firewall barrier sealed. Leave the battery's negative terminal disconnected while this lead has bare ends.
3 Route the power wire along the sill
Lead the power wire rearward beneath the door sill trim on one side of the car. Tuck it under the kick panel and sill plate so it stays hidden and protected from foot traffic, and keep it clear of the pedals and any moving trim as it heads toward the rear.
4 Feed the cables to the trunk under the seat
Carry the power lead and the RCA signal cables toward the back and pass them through the opening beneath the seat. The first-gen CL has a gap on each side of the car that lets a cable drop straight down toward the trunk area, so both the low-level signal lines and the power line can be delivered rearward through it.
5 Alternative: fish the wires with a coat hanger
If a cable snags, straighten a wire coat hanger and use it as an improvised fish tape. Work it in from behind the driver-side rear seat and down toward the trunk, then peel back the trunk carpet and feel for the tip to grab it and draw the cable through. This goes much faster with a helper — one person pushes the hanger while the other retrieves it from the trunk.
6 Mount the amplifiers to the seat backs
Fix the amplifiers to the rear face of the folding seat backs. This keeps them close to the enclosure, off the trunk floor, and easy to reach. Anchor each amp to solid backing and leave room around it for airflow so it can shed heat. Ground each amplifier with a short, clean lead to bare chassis metal nearby rather than running a long ground back to the battery.
7 Connect the system and test
At the trunk, land the power lead on the amplifier, connect the RCA cables coming from the aftermarket head unit, and run the remote turn-on wire so the amps switch on with the stereo. Wire the subwoofer enclosure to the sub amplifier and the 6x9 speakers to the second amp. Reconnect the battery, power up, and confirm both amplifiers switch on and play cleanly before you refit the trim panels.
Pro Tips
- 💡 Fishing the wires is far easier as a two-person job — one to push the hanger from the cabin, one to catch it under the trunk carpet.
- 💡 Reuse the factory firewall grommet instead of drilling a new hole; it keeps the firewall sealed against water and fumes.
- 💡 If you also plan to lay sound deadening, pull the trunk carpet first and route the wires while the floor is exposed.
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