How To Bypass A Factory Amplifier

by Matthew David | Updated: 09/14/2023

How To Bypass A Factory Amplifier

So you just got your hands on a sweet new ride, but the sound system leaves something to be desired. The tinny speakers and underpowered amplifier aren’t exactly pumping out the high-quality jams you were hoping for. You could crank up the volume to drown it out, but who wants distorted music blaring in their ears?

The good news is you don’t have to live with lackluster factory audio. With a few tools and some know-how, you can bypass that wimpy built-in amp and upgrade to an aftermarket system that really rocks. This comprehensive guide will walk you through the entire amplifier bypass process step-by-step.

Ready to give your factory sound the old heave-ho? Let’s get started!

Gather Your Materials

Before any wires get snipped or speakers disconnected, you need to stock up on the right gear for getting the job done. Here’s a list of must-have tools and supplies:

Wire Strippers and Cutters

These allow you to remove insulation and cut wires cleanly. Invest in quality tools so you don’t end up with frayed connections.

Crimpers or Soldering Iron

For connecting wires, you can crimp metal sleeves over stripped ends or solder them together. Either method works as long as the joins are solid.

Electrical Tape

Once connections are made, wrap them in electrical tape to prevent shorts. The tape also lends a professional touch.

Digital Multimeter

This handy gadget lets you trace electrical circuits and identify wires. Setting it to continuity mode is especially useful for tracking speaker cables.

Tone Generator

Sends test tones to confirm correct speaker wire connections. Matching the phase for each speaker results in better sound.

Butt Connectors or Solder

Choose crimp connectors or soldering supplies based on your preferred connection method. Quality materials prevent faulty joins.

Zip Ties

Neatly bundle and secure wires out of harm’s way. Stray cables can get snagged and tear loose.

9-Wire Cable

For extending speaker wires or making new amplified signal runs. Pick a gauge suited for your system’s power.

Locate the Factory Amp

The first step is tracking down exactly where the factory amplifier is installed. Since amp locations vary by vehicle make and model, consulting your owner’s manual is advised. You can also call your dealership’s service department to request specifics about your car.

Once you’ve got the details, it’s time to put your head under the dash or trunk and hunt for the sneaky amp. Inside the housing, you should see wiring harnesses plugged into the inputs and outputs. Inspect all connections for damage before handling anything further.

ID Those Hidden Wires

Now for the fun part: figuring out which wires go where so you can connect the proper channels later. With the factory radio removed, locate the harness that was plugged into the rear. These wires carry the audio signal output that used to go to the amp.

To determine which wires match up, set your multimeter to continuity mode. This allows you to trace electrical paths between points. Touch your test probes to the radio harness one at a time while probing the amplifier side. When the meter beeps, you’ve found a match! Label each pair as you discover them.

If colors don’t correspond, don’t sweat it. Just keep meticulously testing until all input and output pairs are identified. Be sure to also locate the power and ground wires. Pro tip: Those tend to use thicker gauge.

Verify Speaker Hookups

So you’ve got the signal wires figured out, but what about the business end? Making sure the speaker cables are properly matched up is crucial. If polarity is flipped, you’ll face all kinds of sound issues like weak bass and vocals that seem off-center.

First, unplug all speakers and note which wire pair goes to each. With speakers still removed, do a continuity check starting from the amplifier outputs to confirm connections.

Once that’s done, reconnect the speakers without hooking up the amp wire pairs. Then grab your trusty tone generator and attach the leads to speaker cables one-by-one. The goal is to ID positive and negative for each voice coil.

When the test tone plays, check for the “in phase” light on the generator. If it illuminates, bingo! Mark down which amp wires go to positive and negative terminals so you can connect them correctly later.

Make Those All-Important Connections

Here comes showtime – splicing amplifier wires to the speakers! Start by cutting the amp harness, leaving a few inches of slack on each side. Cap off the former power and ground wires with electrical tape so they don’t short anything out.

Strip about 1/2 inch of insulation from the wire ends and twist matching pairs together firmly. Add crimp connectors or solder to finalize the joins, then wrap everything in tape. Give each joint a gentle pull test to confirm solid connections.

With that step complete, you’ve successfully hot-wired your speakers straight from the head unit. The useless factory amp? Discarded into the annals of audio history.

Testing and Installation

You’re oh so close to hearing the sweet fruits of your amplifier bypass labor. Pop that shiny new aftermarket radio in place and revel in your upgraded tunes. All speaker channels bumping in proper phase should sound tight and balanced.

Check for unwanted engine whine or odd noises that could indicate issues with your workmanship. If any wires look messy, tidy them up with zip ties or tucking. Now is also the time to mount any external amps you plan on adding.

Assuming everything checks out, just sit back and let your new system rock your world! No more lackluster listening thanks to your hand-crafted amplifier bypass. Jam on!

Troubleshooting Tips

Despite your best efforts, hiccups can arise when rewiring factory audio components. Here are some common problems and suggested fixes:

Hopefully these tips will get your system singing again in no time! Always double back to previous steps to confirm work if issues creep up.

Closing Thoughts

Completing your own amplifier bypass can be deeply rewarding, plus you get sweet tunes. Just be sure to take precautions around critical circuits and steering components. If uncertainty strikes, there’s no shame in having a professional handle the tricky stuff.

Either way, we hope this guide gave you a helpful overview of the steps and tools involved. Now get out there, tear into that lackluster factory audio and unlock the full potential of your car’s soundtrack! Your ride’s acoustics will thank you.