
INSTALLATION INSTRUCTIONS
AXSUB-FD3
AxxessInterfaces.com © COPYRIGHT 2025 METRA ELECTRONICS CORPORATION REV. 6/5/25 AXSUB-FD3
INTERFACE COMPONENTS
• AXSUB-FD3 interface
• AXDSPX-FD3 vehicle T-harness (LD-DSP-FD3)
• Bass knob (LD-BASSKNOB)
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TOOLS REQUIRED
TABLE OF CONTENTS
Connections ........................................................... 2
Programming ........................................................3
Testing ...................................................................3
Specifications ........................................................3
Troubleshooting....................................................4
• Crimping tool and connectors, or solder gun,
solder, and heat shrink • Tape • Wire cutter
• Zip ties • Multimeter
If the vehicle is equipped with Active noise
cancelation (ANC) microphones, they
will need to be bypassed. Please refer
to Axxessinterfaces.com for ANC bypass
harnesses offered for select vehicles.
INTERFACE FEATURES
Add-a-Sub Data Interface
Fits Select Ford Models 2018-2025
• Designed for amplified and non-amplified systems
• 2-channel non-fading 5V RMS output
• Fixed low-pass frequency of 234Hz
• 250mA remote turn-on output
• Bass knob & vehicle-specific harness included
• Install done at radio location
• Micro “B” USB updatable
Visit AxxessInterfaces.com for more detailed
information about the product and up-to-date
vehicle specific applications.
www.MetraOnline.com
For Dash Disassembly Instructions, refer to
metraonline.com. Enter the year, make, and
model of the vehicle in the Vehicle Fit Guide
for Radio Install kits.
ATTENTION: With the key out of the ignition,
disconnect the negative battery terminal before
installing this product. Ensure that all installation
connections, especially the air bag indicator lights, are
plugged in before reconnecting the battery or cycling
the ignition to test this product.
NOTE: Refer also to the instructions included with the
aftermarket accessory before installing this device.