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GROM-i3 Bluetooth Installation & Operation Guide


Chapter 1 – Getting Started

1.1 Subject
The GROM Audio Bluetooth Dongle —seamless Bluetooth integration into factory car stereo for many car makes. When connected to the extension port of GROM-USB2i adapter, the dongle provides wireless handsfree with the dial/accept/reject call feature. The GROM-BTD also enables wireless A2DP playback with AVRCP control.

1.2 Introduction
Thank you for purchasing the GROM Audio Bluetooth Dongle. With the Bluetooth Dongle you will be able to:

  • use your phone in your car hands free;
  • stream your MP3 or internet radio music and control it where applicable with the stereo buttons;
  • hear the GPS voice announce and more.

To ensure that your Bluetooth module performs correctly in your car or truck, we recommend that you read this entire manual before attempting install and use the GROM Bluetooth dongle.

1.3 Precautions
Proper mounting location. Securely install the interface in a location that is free from heat, humidity, moving parts, or direct sunlight. Avoid the hot airflow from your vehicle’s climate control system. We recommend securing the interface to a suitable location that is free of sharp metal edges using double-sided tape, Velcro, or wire ties.

1.4 Disclaimer

  • This product is not affiliated with any OEM manufacturers.
  • The purchase of this product carries with it no warranties, either expressed or implied.
  • While every care has been taken to provide a quality product, we cannot guarantee that the GROM Bluetooth Dongle will function correctly if installation or operation of the unit is not done according to the instructions provided in this guide.
  • Keep your eyes on the road while driving!
  • We are not liable for the misuse of this product. Misuse includes improper installation, damage to the product and its parts while trying to install it, and the illegal use of the product.

1.5 Completeness of set
The GROM Bluetooth Dongle set consists of:

  • A. BTD dongle with 5FT wiring cable for GROM-USB2 adapter interfaces
  • B. Omnidirectional microphone with swivel mount for easier installation and 10Ft cable


Chapter 2 – General Installation

2.1 Update the firmware on your GROM USB2 unit:
Update firmware of the GROM USB2 interface to the latest version applicable to your vehicle. Firmware is available at http://www.gromaudio.com/software.html. Please follow to the directions posted on the website carefully and make sure that you download the firmware applicable to your vehicle.

2.2 Installation location:

  • 1. Connect the GROM-BTD 8 pin connector to the EXT/iPod port of the GROM-USB2 interface. Mount GROM-BTD module away from metal structures in the dash and near to the phone as best as possible.
  • 2. Choose a proper mounting location for the microphone either on the headliner or center overhead console. Avoid mounting the microphone by the side windows to eliminate extra noise. Please also avoid mounting behind visor to avoid blocking voice from reaching the microphone. Carefully route the microphone cable down into the dash where the GROM-BTD is installed. Connect to the female audio plug on the GROM-BTD to the microphone.
  • 3. Once all connected, cycle the ignition ON-OFF-ON to initialize. Maximum range of GROM-BTD is approximately 20 feet.

2.3 Pairing with the Phone
You need to pair the phone with your Bluetooth receiver only once.

  • 1. Please make sure that Bluetooth function on your phone is active or turned on and that the phone is set to be discoverable. Refer to your phone’s user manual to learn how to turn on and initiate the pairing feature.
  • 2. Turn ON vehicle and radio. GROM-BTD will become discoverable by your phone for 3 minutes. You must pair your phone within that interval.
  • 3. The pairing needs to be performed only once. After pairing is completed your phone will automatically connect to GROM-BTD upon ignition start (whether radio on or off).

NOTE1: Your phone can ask for the confirmation and you can get the pop-up message “Confirm that the passkey “…” is shown on GROM-CAR”. Click “PAIR” then.
NOTE2: Some phones can ask for pin code. Please enter 0000.
NOTE3: The radio must have GROM adapter activated by being in either USB/iPod/AUX mode for the GROM-BTD to function. If not in GROM mode the GROM-BTD will automatically disconnect from your phone and the handset must be used to make or receive calls. If radio is OFF, and you are receiving a call, you can answer automatically by turning ON radio and selecting GROM mode.

2.4 Operating with more than one playing source connected.
If you have any audio player connected to the GROM-USB2 via AUX port – please disconnect the player. You can leave AUX cable in its place. GROM-BTD will not be able to mute the audio player connected via AUX cable.

You don’t have to disconnect the USB drive since it will be automatically muted once GROM-BTD is in use.

2.5 Using your phone in the hands-free mode
Once the Bluetooth is paired with the phone and the stereo is in GROM-USB mode (USB/iPod/AUX) you can start using your phone hands free. Once you receive the phone call the stereo will mute and you will hear the incoming call. Once you receive the call you are able to:

  • 1. Answer Call – Press next track or track up.
  • 2. Reject Call – Press previous track or track down.
  • 3. End Call -- Press previous track or track down.
  • 4. Call Waiting (answer a second call) -- Press next track or track up.

To make the phone call:

  • 1. Dial the phone number on your phone.
  • 2. Once the phone is dialing the music mutes and you start hearing the dialing. Once the phone is answered you will start using it hands-free.
  • 3. Call Last Number – Press SCAN twice within 1-2 seconds.

NOTE: If your stereo is in the different then GROM-USB mode (FM, XM, etc..) and you receive the phone call – please enter the GROM-USB mode by selecting it on the car stereo.

2.6 Streaming your music wirelessly and using A2DP Audio Controls
With the GROM Bluetooth Dongle you are able to stream the music from your mobile phone directly to the car stereo system wirelessly and control it with the car stereo/steering wheel controls.

  • 1. When A2DP (advanced audio distribution profile) music starts playing, other audio will mute and A2DP will play.
  • 2. To stop music playing -- stop playback on your phone. GROM-USB will resume playback the previously selected source.
  • 3. Control A2DP music track selection by using track up and track down on car stereo or steering wheel buttons.
  • 4. Changing car radio mode to the one different then GROM-USB2 (AM,FM, SAT, etc..) will stop A2DP playback.


Chapter 3 – Troubleshooting & Support

Symptom Cause Remedy
After firmware update GROM-USB is not being recognized by the stereo. The wrong firmware is uploaded onto the GROM-USB2 module. Please make sure that you download the correct firmware applicable to your vehicle. Please carefully follow to the firmware update instructions on the GROM-U2i firmware upgrade page.
I cannot pair my phone with GROM Bluetooth. You are not pairing within the 3 minute pairing timeframe. Once you turn on the vehicle the GROM-BTD becomes discoverable for 3 minutes. You must pair your phone within that 3 minute interval.
I cannot pair my phone with GROM Bluetooth. Your phone needs to be reset. Please reset your phone and try to pair again. You can reset your phone by turning it off and on or pulling the battery out.
I cannot pair my phone with GROM Bluetooth. The GROM unit can only support 2 paired devices. Multiple attempts to pair may cause issues. It must be reset. Please reset BTD unit:
1. Switch off GROM mode (go to FM for example).
2. Wait for 3-4 seconds.
3. Switch to GROM mode and after 1 second press SCAN, MIX or RPT button.
4. You will hear low beep confirming the reset.
The sound from the microphone is distorted or muted. The microphone is not positioned correctly. Please make sure to position the microphone in a location free from obstruction and facing the user.

For questions or technical support please contact us via web form. Your question will be answered within next business day.



ToolsDo It Yourself Installation.
The installation is design to be a plug-and-go setup. Connect one end to the CD changer port on the back of the car radio and the other end into your iPhone, iPod.

HelpNeed more help or information?
Locate an installer, refer to the FAQ's or contact us.