Axxess GMOS-MOST-01 Installation Instructions Manual

GMOS-MOST-01

INSTALLATION INSTRUCTIONS

AxxessInterfaces.com © COPYRIGHT 2018 METRA ELECTRONICS CORPORATION REV. 9/28/18 INSTGMOS-MOST-01

Attention! Let the vehicle sit with the key

out of the ignition for a few minutes before
removing the factory radio. When testing the
aftermarket equipment, ensure that all factory
equipment is connected before cycling the
key to ignition.

INTERFACE FEATURES

INTERFACE COMPONENTS

TOOLS REQUIRED

• Crimping tool and connectors, or solder gun,
solder, and heat shrink

• Small flat blade screwdriver • Tape

• Wire cutter • Zip ties • T-15 Torx screwdriver

TABLE OF CONTENTS

Connections .........................................................2-3

Installation .............................................................4

Programming .........................................................4

Audio level adjustment ........................................4

GM MOST® Amplifier Interface 2014-up*

APPLICATIONS

• Provides accessory power
(12-volt 10-amp)

•

Maintains the retained
accessory power (R.A.P.) feature

• Retains OnStar / OE Bluetooth

• Retains warning chimes

• Provides NAV outputs (parking
brake, reverse, speed sense)

• Prewired ASWC-1 harness
(ASWC-1 sold separately)

• Retains the factory AUX-IN jack

• Retains the factory backup
camera

• Used in MOST® amplified
applications

• Retains balance

• Micro B USB updatable

CHEVROLET

Colorado 2015-2018
Silverado 1500 2014-2018
Silverado 2500/3500 2015-2018

Suburban 2015-up
Tahoe 2015-up

GMC

Canyon 2015-2018
Sierra 1500 2014-2018

Sierra 2500/3500 2015-2018
Yukon / Yukon XL 2015-up

*Visit AxxessInterfaces.com for up-to-date vehicle specific applications.

• GMOS-MOST-01 interface

• GMOST-MOST-01 harness

• 16-pin harness with stripped leads

• Backup camera harness

• 10-pin jumper harness

• 12-pin jumper harness

2

CONNECTIONS

From the 16-pin harness with stripped leads to the aftermarket radio:

• Connect the Red wire to the accessory wire.
Note: If installing an ASWC-1 (sold separately), there will be an accessory wire on the 12-pin

pre-wired ASWC-1 harness to connect as well.

• Connect the Orange/White wire to the illumination wire. If the aftermarket radio does not
have an illumination wire, tape off the Orange/White wire.

• Connect the Blue/White wire to the amp turn on wire. This wire must be connected to hear
sound from the factory amplifier.

• If also installing an ASWC-1 (not included), connect the Brown wire to the Brown wire in the
12-pin pre-wired ASWC-1 harness.

• Connect the Gray wire to the right front positive speaker output.

• Connect the Gray/Black wire to the right front negative speaker output.

• Connect the White wire to the left front positive speaker output.

• Connect the White/Black wire to the left front negative speaker output.

• Connect the Green wire to the left rear positive speaker output.

• Connect the Green/Black wire to the left rear negative speaker output.

• Connect the Purple wire to the right rear positive speaker output.

• Connect the Purple/Black wire to the right rear negative speaker output.

The following (3) wires are only for multimedia/navigation radios that require these wires.

• Connect the Light Green wire to the parking brake wire.

• Connect the Blue/Pink wire to the speed sense wire.

• Connect the Green/Purple wire to the reverse wire.

From the GMOS-MOST-01 harness to the aftermarket radio:

• Connect the Black wire to the ground wire.

• Connect the Yellow wire to the battery wire.

• Connect the Brown wire, to the Brown wire from the

16-pin harness with stripped leads

.

• If retaining the factory AUX-IN jack is desired, connect the Red and White RCA jacks to the

audio AUX-IN jacks from the aftermarket radio.

Note: a) The jack can only be used if it is a single jack.
b) If the jack has a USB port as well, neither can be retained.

• Disregard the Red wire, it will not be used in this application.

12-pin pre-wired ASWC-1 harness

This harness is to be used along with the ASWC-1 (sold separately) to retain steering wheel audio
controls. If the ASWC-1 is not being used, disregard this harness. If it will be used, please refer to
the following instructions, and the ASWC-1 instructions for radio connections and programming.

Disregard the harness that comes with
the ASWC-1.

• Connect the Red wire to the

accessory wire.

•

Connect the Green/Black wire, to the
Green/Black wire in the 8-pin Black
connector located in the steering
column. (Figure A)

(Figure A)

Green/Black wire

Continued on the next page

• Connect the Brown wire to the Brown wire from the 16-pin harness with stripped

leads.

3

REV. 9/28/2018 INSTGMOS-MOST-01

CONNECTIONS (CONT)

DIN jack:

Disregard the DIN jack, it will not be used in this application.
Note: The relay attached to the GMOS-MOST-01 harness is only for audible turn signal clicks. No

extra steps are required to retain this feature, so leave the relay as-is.

From the backup camera harness:

To the aftermarket radio:

• Connect the Yellow RCA jack to the BACKUP CAMERA input.

To the vehicle:

• Connect the

backup camera harness

, to the male Gray connector removed from the Human

Machine Interface module (HMI). (Figure B)

For the Chevy Colorado and GMC Canyon:

• The HMI module is located in the radio cavity, down low.

For all other models:

• The HMI module is located behind the glove box. There are (2) modules behind the glove
box. The HMI module is behind the metal dashboard support. (Figure C)

• Drop the glove box down by first removing the retaining cable on the right side. Then
squeeze the glove box sides and gently pull down.

• Remove (6) T-15 Torx screws securing the plastic panel now exposed.

From the 10-pin or 12-pin jumper harness to the vehicle:

If the vehicle

does not

have a CD or DVD-Drive, disregard these steps.

For models

without

rear seat entertainment:

• Connect the

female

Black 10-pin jumper harness, to the

male

Black 10-pin harness

removed from the CD-Drive.

For models

with

rear seat entertainment:

• Connect the

female

Black 12-pin jumper harness, to the

male

Black 12-pin harness

removed from the DVD-Drive.

Note: Even though this step must be done for models with rear seat entertainment,
the rear seat entertainment system will not be retained by this interface.

(Figure B)

Human Machine Interface module

(Arrow points to the location)

(Figure C)