TOP VEHICLE TECH GR3MBZ1 User manual

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The informaon provided in this document is subject to change without noce due to changes and/or
improvements to the product/s.
This dash image is a visual representaon for display purposes only.
V1.0522
GR3MBZ1
INSTALLATION MANUAL
MERCEDES BENZ
C-CLASS (W203)
2001-2004

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ABOUT THIS PRODUCT
The GR3MBZ1 installaon kit allows for the retenon of the vehicle’s steering wheel controls and maintains
the original aesthec of the interior when installing a new car stereo. The GR3MBZ1 gives you everything you
need for a complete install in one box. The components of this kit are compable for the Mercedes Benz C-Class
(W203, 2001-2004) with non-amplied Audio10/30 stereos. The wiring harness and interface will help to retain
the steering wheel controls with the new stereo.
Supplied with a 10-Way ISO connector.
CUSTOMER SUPPORT
Installaons should be carried out by, or under the guidance of an experienced installer. If you do encounter any
problems during the installaon of this product, then please contact our dedicated customer service team at:
Phone: [phone] E-Mail: [e-mail]
CONTENTS
• 1x Fascia plate (with accessories)
• 1x Instrucon manual
• 1x Steering wheel control harness and interface
• 1x Antenna adapter
• 1x DAB antenna adapter
• 1x Stereo patch lead

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FITTING GUIDE
1. Start by loosening the gear shi surround, then using a bojo tool, unclip the centre console trim and pull
it forward, out of the dashboard.
1. Open the passenger side door and proceed to pull away the door trim from the pillar.
STEREO REMOVAL
DAB ANTENNA INSTALLATION
2. Using a set of panel removal tools, begin to pry away the pillar casing.
4. The DAB antenna not only has a self adhesive backing, but also features a black earth sheet. When
placing the DAB antenna, the earth sheet MUST be placed onto the metal part of the pillar. The antenna
itself must be located roughly 15cm from the top of the windscreen.
Note: this antenna must not be placed atop any kind of heang elements, this will interfere with the
antenna’s signal.
5. Once happy with the placement, take the 3m of wiring extension and feed it down through to the
stereo’s opening. With the wiring adjusted to the appropriate length, feel free to re-install the glovebox.
3. The glovebox will need to dropped down to route the antennas wiring. To do this you will need to take
o the side panel and remove 2x screws on the side, 3x screws within the top lip, as well as 2x screws
underneath. Once free, drop down and leave in the footwell.
2. With the centre console trim removed, unclip the locater clips located at the front of the ashtray panel.
When these are loose, simply pull the ashtray out of the dashboard.
FASCIA PLATE SET-UP
1. Take the new fascia and locate it into the dashboard using the pre-exisng screws.
3. With the cage secured into place, and once the “Stereo Installaon” process is complete, simply slide
the stereo into the fascia and re-assemble the dashboard.
2. Take the pocket and install it into the preferred aperture (most commonly this is installed within the
boom port).
3. Unclip the omni-direconal fan locator clips within the air vent to allow the vents to excced their normal
rotaon. This will then allow you to remove 2x screws located in the boom corners of the vent.
4. Once you have removed these screws, use a bojo tool to unclip the top of the air vents and remove it
from the dashboard.
5. With the top 2x screws removed on the main fascia, now proceed to remove the 2x screws at the very
boom of the fascia. Once done, unclip the two clips found next to the screws.
6. Once these 2x locater clips are undone, remove the main fascia whilst disconnecng the wiring.
7. With the fascia out of the way, remove the 2x screws that hold the main radio in place. Once free,
remove it from the dashboard whilst disconnecng all of the wiring.

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FITTING GUIDE
STEREO INSTALLATION
6. When all the above wires (and any addional accessories) have been connected, nally make the
connecons between the stereo and the vehicles pre-exisng power/stalk connectors.
3. Connect the DAB antenna’s SMB connector to the back of the new stereo.
4. Aach the antenna adapter to the vehicles pre-exisng connecon and the back of new stereo.
5. Aach the addional wiring on the harness to the back of the stereo:
Pink - Speed Pulse Green - Park Brake Purple - Reverse
1. Take the steering wheel control interface in hand and connect both the 12-way stereo patch lead and
the 14-way steering wheel harness connectors to the corresponding sides.
2. Connect the bullet connector from the stereo patch lead to the ‘steering wheel remote input’ on the
back of the new stereo.

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Please note: conguraon layout may dier dependent on vehicle model.
STEERING WHEEL CONTROL FUNCTIONALITY
12
3
4
5
1. Source
2. Track +
3. Track -
4. Volume +
5. Volume -
1. Menu Up
2. Arrow Up
3. Arrow Down
4. Volume +
5. Volume -
Original Buon New Funcon

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ISO Connector
Connect to new stereo
10-Way ISO Connector
Connect to relevant connector from vehicle
Main Wiring Loom
Connector [14 Pin]
Connect to Interface Box
Interface Box
Flying Wires
Pink - Speed Pulse
Green - Park Brake
Purple - Reverse Gear
Stereo Patch Lead Connector [12 Pin]
Connect to Interface Box
Note: Must be connected first, before
power connection is made to the
interface
Stereo Patch Lead Bullet Connector
Connect to ‘Steering Wheel Remote
Input’ on back of the stereo.
WIRING DIAGRAM

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NOTES

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If at any point you experience any problems and need any assistance before, during or aer the
installaon process, please contact us via :
Phone: [phone]
E-Mail: [e-mail]
Mon - Fri 9am - 5.30pm GMT
TECHNICAL ASSISTANCE
If you would like to download a digital copy of this manual, or any other product, then please
visit the www.topvehicletech.com website.
This manual is considered correct at the me of prinng but is subject to change. For the latest
manuals & updates, refer to our website.
Copyright 2022 by TopVehicleTech.
All rights reserved. No part of this publicaon may be reproduced, distributed or transmied
in any form or by any means, including photocopying, recording, copying or other electronic or
mechanical methods, without the prior wrien permission of the author.