1. Introduction
The PAC AmpPRO 4 AP4-CH21 is an amplifier replacement interface designed to integrate an aftermarket amplifier into select Chrysler, Dodge, Jeep, and Ram vehicles. This module allows for the replacement of the factory amplifier with a more powerful aftermarket unit while retaining essential vehicle audio features such as warning chimes, navigation prompts, and Bluetooth functions. The system provides preamp-level outputs for connection to an aftermarket amplifier, ensuring full control over your audio system.
2. Product Overview
The AmpPRO 4 AP4-CH21 system consists of a main interface module and a vehicle-specific T-harness. This design facilitates a streamlined installation process. The module converts the factory radio's speaker outputs into six preamp-level outputs, suitable for connection to an aftermarket amplifier.
Image 2.1: The PAC AmpPRO 4 AP4-CH21 interface module and accompanying T-harness. The module is compact, designed to fit behind the vehicle's dashboard, and the T-harness connects directly to the factory radio and vehicle wiring.
Key Features:
- Interface module for amplifier replacement or addition.
- Compatible with vehicles equipped with a data bus premium sound system.
- Plug-and-play installation using a vehicle-specific T-harness.
- Provides 5-channel RCA outputs for aftermarket amplifiers.
- Includes an amplifier turn-on trigger wire.
- Features a non-fading level control knob for subwoofer adjustment.
- Delivers a flat audio output for a solid foundation for sound customization.
- Retains factory features such as uConnect, Bluetooth audio, and all warning chimes.
- Eliminates the need for external summing and DSP devices.
- Customized OEM bass, mid, and treble center frequency selection via PC App.
3. Compatibility
The PAC AmpPRO 4 AP4-CH21 is compatible with select 2007-2017 Chrysler, Dodge, Jeep, and Ram vehicles. It is specifically designed for vehicles equipped with a data bus premium sound system. Verify your vehicle's specific year, make, and model against the manufacturer's compatibility list before installation.
4. Setup and Installation
Installation of the AmpPRO 4 AP4-CH21 involves connecting the T-harness to the factory radio and vehicle harness, then connecting the module. The module should be placed in a secure location behind the dashboard.
Installation Steps:
- Disconnect Vehicle Battery: Before beginning any electrical work, disconnect the negative terminal of the vehicle's battery to prevent electrical shorts.
- Access Factory Radio: Carefully remove the necessary trim panels to gain access to the factory radio.
- Connect T-Harness: Disconnect the factory harness from the back of the radio. Connect the AmpPRO T-harness inline with the factory radio and vehicle harness.
- Connect AmpPRO Module: Plug the other end of the T-harness into the AmpPRO 4 AP4-CH21 module.
- Route RCA Outputs: Connect your aftermarket amplifier's RCA input cables to the 5-channel RCA outputs on the AmpPRO module. Route these cables to your amplifier.
- Connect Amplifier Turn-On Wire: Connect the amplifier turn-on trigger wire from the AmpPRO module to your aftermarket amplifier's remote turn-on input.
- Install Remote Level Control: If using, install the wired remote level control in a convenient location for subwoofer volume adjustment. Connect it to the designated port on the AmpPRO module.
- Secure Module: Secure the AmpPRO module behind the dash, ensuring it is not obstructing any moving parts or ventilation.
- Reconnect Battery: Reconnect the vehicle's battery.
- Test System: Power on the vehicle and test the audio system to ensure all functions are working correctly.
Optional Add-on: The PAC APA-TOS1 adapter (sold separately) can be connected to the AmpPRO module to provide an optical digital output for high-end digital processors and amplifiers.
5. Operating Instructions
Once installed, the AmpPRO 4 AP4-CH21 allows your factory radio controls (volume, balance, and fade) to function as before for your front and rear speakers. The wired remote level control provides independent adjustment for the subwoofer channels.
AmpPRO PC App:
The AmpPRO PC App provides advanced customization and control. Download the application to a Windows-based PC and connect the AmpPRO module via USB. The app allows you to:
- Access and customize the factory 3-band parametric equalizer (EQ).
- Adjust the system's minimum volume level.
6. Maintenance
The PAC AmpPRO 4 AP4-CH21 is designed for long-term, maintenance-free operation. Ensure the module is securely mounted and all connections are tight. Avoid exposing the module to extreme temperatures or moisture. Periodically check for firmware updates using the AmpPRO PC App to ensure optimal performance and access to the latest features.
7. Troubleshooting
If you encounter issues with your AmpPRO 4 AP4-CH21, consider the following troubleshooting steps:
- No Audio Output: Verify all connections, especially the T-harness to the factory radio and the RCA outputs to the aftermarket amplifier. Ensure the amplifier is powered on and receiving a remote turn-on signal.
- High Noise Floor / Hissing: Check all ground connections for the amplifier and the AmpPRO module. Ensure RCA cables are routed away from power wires to prevent interference. Adjust the minimum volume level using the AmpPRO PC App.
- Engine Noise / Alternator Whine: This can indicate a grounding issue. Ensure all audio components, including the AmpPRO module and amplifier, have clean, secure ground connections. Try a different grounding point if necessary. Check for proper shielding of RCA cables.
- Incorrect Volume/Balance/Fade: Confirm that the factory radio controls are functioning correctly. If issues persist, ensure the AmpPRO module is correctly configured via the PC App.
- App Connection Issues: Ensure the USB cable is properly connected between the module and your Windows PC. Verify that the AmpPRO PC App is installed correctly and that no other applications are interfering with the USB connection.
- Firmware Update Failure: Ensure a stable USB connection and power supply during the update process. Do not disconnect the module or power off the PC during an update.
For further assistance, refer to the official PAC support resources or contact their customer service.
8. Specifications
| Specification | Value |
|---|---|
| Item Model Number | AP4CH21 |
| Brand | PAC |
| Item Dimensions (L x W x H) | 6 x 2 x 2 inches |
| Item Weight | 12 ounces |
| Voltage | 5 Volts |
| Maximum Supply Voltage | 12 Volts (DC) |
| Minimum Supply Voltage | 12 Volts (DC) |
| Number of Channels | 5 |
| Mounting Type | Surface Mount |
| Specification Met | FCC |
| UPC | 609098819961 |
9. Warranty and Support
Specific warranty information for the PAC AmpPRO 4 AP4-CH21 is typically provided with the product packaging or available on the manufacturer's official website. Please refer to these resources for detailed warranty terms and conditions. For technical support, product registration, or additional inquiries, visit the official PAC website or contact their customer service department directly.
