Quick Start Guide
REV. 4/1/2019 INST99-3028S
9
INTERFACE FEATURES
INTERFACE COMPONENTS
•  Axxess interface
•  3028 harness
•  Climate control harness
•  16-pin harness with stripped leads
•  4-pin to 4-pin resistor pad harness
•  Female 3.5mm connector with stripped leads
TOOLS REQUIRED
• Crimping tool and connectors, or solder gun, solder, and heat shrink 
• Small flat blade screwdriver • Tape • Wire cutter • Zip ties
TABLE OF CONTENTS
Connections .............................................................................................................................10-13
  For models 
without
 an amplifier ......................................................................................10-11
  For models 
with
 an amplifier ............................................................................................12-13
Installation ...................................................................................................................................13
Programming ...............................................................................................................................14
Adjustments .................................................................................................................................14
Steering Wheel Control Settings ...........................................................................................16-18
Troubleshooting ...........................................................................................................................19
•  Provides accessory power (12-volt 10-amp)
•  Maintains the Retained Accessory Power (R.A.P.) feature
•  Provides NAV outputs (parking brake, reverse, speed sense)
•  Retains warning chimes
•  Retains OnStar/OE Bluetooth
•  Adjustable volume for chimes and OnStar
•  Retains the factory AUX-IN jack
•  Retains audio controls on the steering wheel
•  Can be used in non-amplified, or amplified models
•  Retains balance and fade
•  Micro-B USB updatable
Attention! This interface will work with models that are either non-amplified or amplified, 
Please follow the instructions carefully for your model vehicle. Failure to do so will result in 
either no sound, or low sound. If you are unsure if your vehicle is factory amplified or not, 
please contact your local dealership.
AXXESS INTERFACE INSTALLATION










