Navigating the installation of a new Pioneer AVH-P3200DVD head unit can sometimes present unexpected wiring challenges, especially when it comes to bypassing the parking brake requirement to enable full functionality. Many users, like yourself, turn to online resources such as YouTube tutorials for guidance, but specific scenarios can still leave questions unanswered. Let’s break down the grounding concerns you’ve encountered with your Pioneer AVH-P3200DVD installation and clarify the wiring for a successful parking brake bypass.
You’ve correctly identified the common method of bypassing the parking brake limitation, likely involving a relay and some creative wiring to simulate the parking brake being engaged. Your primary concern revolves around the wires circled in red in the provided image, specifically regarding grounding and the “Subaru only” wire from your Crutchfield harness.
Understanding the “Subaru Only” Wire
The black wire tagged “Subaru only” from your Crutchfield harness is indeed a ground wire. In Subaru vehicles, this wire might serve a specific grounding purpose related to the factory radio or vehicle chassis. However, for your Pioneer AVH-P3200DVD installation and the parking brake bypass, this wire is generally not needed and can be treated as a standard ground.
Your initial instinct is correct: if you were not performing the bypass, this “Subaru only” wire, if needed in your Subaru, would typically be connected to the vehicle chassis ground, alongside the black ground wire from the Pioneer head unit harness.
Resolving the Grounding for Parking Brake Bypass
The crucial point in your question lies in how to achieve a proper ground in conjunction with the parking brake bypass. The YouTube videos you watched likely demonstrate splitting the Pioneer harness’s ground wire to connect to both the relay and potentially the head unit itself. Your concern that this split might compromise the ground is valid and highlights a common point of confusion.
To clarify, when performing the parking brake bypass, you still need to ensure the Pioneer head unit receives a solid ground connection. Here are a few options to address your grounding question, keeping it straightforward:
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Utilizing the “Subaru Only” Wire: You can indeed use the “Subaru only” wire as an additional ground source. Connect this “Subaru only” wire (red circle #1 in your image) together with the black ground wire from the Pioneer harness (part of red circle #2 in your image) and the extra wire for your bypass relay. All these should be securely connected and grounded to a reliable chassis ground point in your vehicle. This approach ensures a robust ground connection even with the bypass in place.
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Dedicated Ground Wire: Alternatively, if you prefer not to use the “Subaru only” wire, you can simply cap it off with electrical tape to prevent any shorts. In this case, ensure the black ground wire from the Pioneer harness (split for the bypass relay) is firmly connected to a clean chassis ground point. You can even add a third wire to this ground connection point, solely dedicated to grounding the bypass relay, if you want to ensure separate grounding paths.
The Correct Approach
Based on your description and the standard parking brake bypass wiring, the most practical and effective solution is to use the “Subaru only” wire as an additional ground. Connect the “Subaru only” wire, the black ground wire from the Pioneer harness, and the ground wire for your bypass relay all together and securely ground them to the vehicle chassis. This method provides a strong, common ground point for both the head unit and the bypass circuit, eliminating any grounding concerns.
By connecting these wires together and grounding them, you ensure that both the Pioneer head unit and the parking brake bypass relay have a proper and reliable ground connection, allowing you to enjoy the full functionality of your new AVH-P3200DVD system without parking brake restrictions. Remember to always ensure secure and insulated wire connections for a safe and functional installation.
