2018-2021 Expedition & Navigator Audio Control Module Issues: From Silence to Solutions

Distinguishing the ACM, APIM, and DSP

When diagnosing audio problems in a 2018-2021 Ford Expedition or Lincoln Navigator, it's crucial to know which module does what. These vehicles use a networked system, and failure can be confusing.

• Audio Control Module (ACM): This is the radio and sound generator. It's the component that tunes stations and creates the audio signal. If your screen works but you have no sound, the ACM is a primary suspect.
• Accessory Protocol Interface Module (APIM): This is the SYNC module that runs the touchscreen display, navigation, Bluetooth connectivity, and apps like Apple CarPlay. A failing APIM often results in a black or frozen screen, or issues with phone pairing.
🎬 Watch: How to fix a black CarPlay screen
• Digital Signal Processing (DSP) Module: This is the amplifier. It takes the low-level audio signal from the ACM and boosts it to power the speakers. Some audio issues, like sudden loud static or no sound, can be traced to the DSP module, which may sometimes be fixed with a software reprogram.

Common Symptoms of a Failing Audio Control Module

A bad ACM can cause a range of frustrating issues. Because it's the heart of the audio system, its failure can seem like a major electrical problem.

• No Sound From Speakers: This is the most common symptom. The radio display appears to be working correctly—you can see the station, song title, and even see the volume level change on screen—but there is complete silence from all speakers.
• Loud Popping or Static: A sudden, loud pop or burst of static from the speakers, sometimes occurring at startup, can be caused by an internal failure in the ACM or the related DSP amplifier. This noise can be startlingly loud, with some owners reporting it at over 100 decibels.
• AM/FM Reception Issues: The radio may have trouble tuning into stations, have very weak reception, or constantly switch between stereo and mono.
• Unresponsive Controls: The volume knob or source selection buttons may stop working, even if other parts of the infotainment system seem fine.
• Warning Chimes Come From the Dash: Ford vehicles route safety chimes (like for an open door or unbuckled seatbelt) through the audio system. If the ACM fails, the vehicle will reroute these chimes to a small speaker in the instrument panel as a backup.
• Radio Will Not Power On: In some cases, a complete internal failure of the ACM can prevent the radio from turning on at all, resulting in a black screen.

Known Issues, TSBs, and Recalls

Several Technical Service Bulletins (TSBs) have been issued for audio concerns in these vehicles. Before replacing parts, it's wise to see if a software update or known repair procedure applies.

• TSB 23-2116: For some 2022 Expedition models, this TSB addresses an inoperative audio system or inability to access radio modes. The cause is identified as potential liquid getting into the ACM from a seam in the dash. The fix involves replacing the ACM and applying a special seal to the dash seam to prevent recurrence.
• SSM 51663: Affecting 2021 Expedition models, this addresses a pop noise or static from the speakers at startup that cannot be controlled. The solution is to reprogram the Digital Signal Processing (DSP) module with the latest software via a dealer's diagnostic tool.
• General Audio Inoperative TSB: For 2021 Expedition and other models, a TSB was released for issues including no audio, chimes defaulting to the instrument cluster, and no communication with the ACM or DSP. The fix is a hard reset by disconnecting the battery, followed by reprogramming the DSP module.
• SYNC 3 Screen Issues: While not directly an ACM issue, TSBs exist for 2016-2018 models with SYNC 3 experiencing intermittent blue or black screens. The recommended fix is a SYNC software update.

Buying a Used Audio Control Module

Purchasing a used OEM ACM can be a cost-effective solution, but there are important factors to consider to ensure you get a good, compatible part.

1. Match the Part Number Exactly

This is the most critical step. Ford uses many different ACM versions depending on the vehicle's options (e.g., standard audio, B&O premium sound, satellite radio). Using an ACM with the wrong part number can result in missing features or complete incompatibility. The part number is printed on a sticker on the module's case. Do not rely on visual appearance alone.

2. Physical Inspection

When you receive the used module, inspect it carefully before installation:

• Connectors: Check all electrical connector ports for bent, corroded, or broken pins. Damage here can cause intermittent issues or prevent the module from working at all.
• Casing: Look for signs of water damage, such as corrosion, water spots, or a white, chalky residue, especially given the issue noted in TSB 23-2116. Avoid any module that appears to have been wet.
• Mounting Points: Ensure all mounting tabs are intact and not cracked or broken.

3. Programming Considerations

While some sources suggest that repairing your original module avoids the need for programming, a used ACM from another vehicle may require programming to match your vehicle's specific configuration. This is often done at a dealership or a qualified independent shop with Ford's diagnostic software (FDRS). Be prepared for this potential extra step and cost when buying a used module.

Cost of Replacement

The cost to fix a faulty ACM can vary significantly depending on the approach you take.

Replacement Guide (Difficulty: 2/5)

Replacing the ACM in the 2018-2021 Expedition and Navigator is a moderately easy job that most DIYers with basic tools can handle. The module is typically located behind the center instrument panel stack, below the touchscreen.

Estimated Time: 1 hour

Tools Needed:

• Trim removal tool kit
• 7mm or 8mm socket and ratchet
• Small flathead screwdriver

Step-by-Step Instructions:

1. Disconnect the Battery: Before working on any electronic components, disconnect the negative terminal of the 12V battery to prevent short circuits.
2. Remove Trim Panels: Use plastic trim removal tools to carefully pry away the trim pieces on either side of the center console and radio/climate control area. These are held in by clips.
3. Access the Module: Once the trim is removed, you will see the mounting screws for the center stack components. The ACM is usually a silver metal box located in this area.
4. Unbolt the ACM: Remove the screws (typically 7mm or 8mm) that secure the ACM to its bracket.
5. Disconnect Wiring: Carefully slide the module out. Press the release tabs on the electrical connectors and unplug them from the back of the module. There will be several connectors for power, speakers, and antennas.
6. Install the New Module: Connect the wiring harnesses to the replacement ACM, slide it back into place, and secure it with the mounting screws.
7. Reassemble and Test: Re-install the trim panels by snapping them back into place. Reconnect the battery, start the vehicle, and test all audio functions, including AM, FM, satellite radio, and Bluetooth.

Frequently Asked Questions (FAQ)