How to Install Subs on a Stock Head Unit

Vehicle owners have many options when upgrading their factory car stereo sound system. You can install aftermarket stereo equipment for a more powerful and complete-sounding stereo. One way to add volume and depth to your car's stereo is by adding subwoofers. You can install amplifiers and subs to your factory stereo head unit or you can install powered subwoofers with built-in amps.

Things You'll Need

• Wrench or pliers
• Amplifier wiring kit (including power cable, signal and turn-on lead cables, and grounding wire)
• Vehicle shop (or repair) manual
• Wiring harness adapter

Instructions

1. Lift the hood of the vehicle to access the battery. Loosen the bolts holding the battery cables to the terminals. Lift the cable's clamps from the terminals and set the negative cable aside. Place the ring terminal from the amplifier wiring kit onto the positive terminal post. Place the positive battery cable clamp onto the terminal and tighten the bolt.

2. Connect the (commonly blue) power supply cable to the ring terminal. Feed the power supply cable through the firewall and into the passenger cabin of the vehicle. Remove the fuse from the fuse holder on the ring terminal and keep it handy for later reinsertion. Move to the interior of the vehicle.

3. Remove the stock stereo head unit from the dashboard stereo dock. Consult your vehicle repair manual for instructions for removing the dash panels and extracting the head unit from the stereo mount. Disconnect the stereo wiring connectors from the outlets on the back of the unit. Plug the stereo wiring connectors from your vehicle into the leads of the wiring harness adapter. Connect the wiring harness adapter lead connectors to the outlets on the stock radio's rear panel.

4. Plug the signal cable and turn-on lead to the wiring harness adapter. See the adapter's manual or follow the color-coding on the leads for proper connection locations. Feed each of the new cables through the back of the stereo dock and down to the floor of the vehicle.

5. Replace the stereo into the dock. Follow the procedures outlined in the repair manual for stereo installation.

6. Route the power cable down the left side (driver's side) of the vehicle to the rear cargo area or trunk. Route the signal and turn-on lead cables down the opposite side of the vehicle to the trunk to prevent interference from the power supply.

7. Place the sub in the rear of the vehicle. Connect the grounding wire (included in the amp wiring kit) from the subwoofer to a screw or bolt near the sub. Any screw or bolt less than 20 inches from the sub and connected directly to the frame of the vehicle is an adequate grounding source.

8. Plug the power supply cable into the power input on the subwoofer. Connect the signal and turn-on leads to the sub. Return to the vehicle's battery.

9. Place the negative battery cable clamp back onto the negative terminal. Tighten the bolt on the clamp to secure the clamp to the post. Replace the fuse into the fuse holder on the ring terminal and close the hood.

References

• Crutchfield: Subwoofer Installation Guide