Honda CR-Z: Adding an Aftermarket Amplifier to the Factory Navigation Audio System
Introduction
This guide covers adding an aftermarket amplifier to a Honda CR-Z fitted with the factory navigation head unit while keeping the original stereo and OEM amplifier fully in place. Instead of replacing the factory gear, the approach taps the audio signal as it travels from the nav head unit toward the factory amplifier, so an added amp runs in parallel to drive a subwoofer or an extra set of speakers for improved staging. A PAC AOEM-HON20 T-harness splices into the factory 20-pin amplifier connector to create that tap, and an optional blitzSafe HON/AUX-DMX V.2X adapter adds an RCA auxiliary input at the factory CD-changer port for external sources such as a DVD player or game console (note: this handles audio only, not video). An early reply assumed the stock amp was being removed; the builder clarified that the OEM amp is retained and only its input signal is tapped. This is a stage-one signal-tap and bench-verification writeup, so final enclosure fabrication and mounting are handled separately. It suits owners who already have amplifier and speaker equipment on hand and want to expand the factory system without losing OEM integration. Adapted from a community writeup by s7park on CRZ Forum (https://www.crzforum.com/threads/diy-amplifier-add-on-part-1.11173/), including corrections from the follow-up discussion.
Reference
Tools Required
- Trim panel pry tools
- Screwdriver or socket for the DIN mounting bolt
- Wire crimpers and RCA/signal cabling
- Test speaker for signal verification
Parts Required
-
PAC AOEM-HON20 amp add-on T-harness ($33.03)
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blitzSafe HON/AUX-DMX V.2X auxiliary input adapter ($120, optional RCA input)
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Aftermarket amplifier
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Crossover
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Additional speakers or subwoofer
Safety Warnings
- ⚠ Disconnect the negative battery terminal before unplugging any audio connectors to prevent shorts to the head unit or amplifier.
- ⚠ The auxiliary and amp-tap adapters pass audio only; do not expect video output on the navigation display from this modification.
Step-by-Step Instructions
1 Confirm applicability and gather the adapters
This procedure applies to a Honda CR-Z running the factory navigation head unit and OEM amplifier. Obtain the PAC AOEM-HON20 amp add-on T-harness ($33.03), which provides the signal tap. If you also want an auxiliary line-level input, obtain the blitzSafe HON/AUX-DMX V.2X adapter ($120). Purchase from a retailer that accepts returns in case an adapter does not fit your specific configuration.
2 Understand the factory signal path
In the CR-Z audio system, the navigation head unit sends its audio output through a 20-pin connector to the OEM amplifier. This connector is the tap point. The goal is to insert the PAC T-harness at this junction so the factory amp still receives its normal input while a duplicate of that signal is made available for an aftermarket amp. The OEM amplifier is not removed from the signal chain.
3 Disconnect power before working on the wiring
Disconnect the negative battery terminal before opening the audio harness to avoid shorting the head unit or amplifier while connectors are unplugged. Allow the system to fully power down before proceeding.
4 Access the OEM amplifier
Remove the surrounding dash and DIN trim to reach the factory amplifier. A third mounting fastener is hidden inside the DIN cavity; locate and remove it to release the amp so it can be pulled out far enough to reach its connector. Keep track of the trim clips and bolts for reassembly.
5 Unplug the 20-pin amplifier connector
With the amp freed, unplug the factory 20-pin harness feeding the OEM amplifier. This is the connection the PAC T-harness will splice into. Inspect the connector orientation and keying so the T-harness is installed the correct way around.
6 Install the PAC AOEM-HON20 T-harness inline
Plug the PAC AOEM-HON20 between the factory 20-pin harness and the OEM amplifier. Because it is a T-style pass-through, the factory amp continues to receive its normal signal while the harness breaks out a parallel copy of the head unit's audio output for your aftermarket amplifier.
7 Add the optional RCA auxiliary input
If you want to feed external sources into the factory stereo, install the blitzSafe HON/AUX-DMX V.2X adapter, which connects at the factory CD-changer input and accepts an RCA line-level signal. This lets a DVD player, game console, or similar device play through the OEM stereo. It carries audio only; displaying external video on the navigation screen requires a separate device.
8 Connect and bench-verify the aftermarket amp
Route the parallel outputs from the PAC harness to your aftermarket amplifier, then feed a crossover and a test speaker. Before finalizing any mounting, power the system and confirm the tapped signal is clean and present on all channels. Only after verification proceed to permanent amp, crossover, and enclosure mounting.
Pro Tips
- 💡 The mod keeps the factory head unit and OEM amplifier intact; you are adding a second amp in parallel, not replacing the stock system.
- 💡 The blitzSafe adapter reuses the factory CD-changer input, so no head unit replacement is needed to gain an RCA aux source.
- 💡 Verify the tapped signal with a crossover, amp, and single speaker before committing to a custom enclosure or permanent wiring.
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