STEP 01
Find an empty station.
Turn on your car radio and choose an unused FM frequency with no station playing. Then plug the FM3 into the powered vehicle accessory socket.
← All product supportTune in.
Product support / FM3 FM transmitter
Tune in.
Drive connected.
Connect your phone, match your radio frequency, and bring music and hands-free calls to your car speakers.
Download FM3 manual ↗01 / Get connected
One frequency. Both devices.
Complete setup while parked. Pick a frequency with no local broadcast before pairing your phone.
STEP 02
Match the FM3 frequency.
Hold the phone button for about 2 seconds until the frequency flashes. Move the control left or right to match the radio. Press it again or wait 3 seconds to exit.
STEP 03
Pair your phone.
Open your phone’s Bluetooth settings and connect to FM3. Enter 0000 only if a PIN is requested. A steady bt on the display confirms pairing.
Example: radio 89.5 = FM3 89.5
The numbers must match. This is an example, not a recommended station for every area—choose a locally unused frequency. If interference appears, change both devices to another empty channel.
02 / Choose your source
Your music, through your speakers.
Press the separate Switch button in music mode to move between Bluetooth and USB flash-drive playback.
Bluetooth from your phone.
After pairing, start music on your phone. FM3 sends the audio to your car radio on the frequency you selected.
FM3 reconnects to the last connected device. After restarting, you may need to resume playback manually on the phone.
Phone → Bluetooth → FM3 → FM radioMusic from a USB drive.
Insert a FAT32 USB flash drive, up to 64GB, into the USB music port. FM3 recognizes the drive and starts playing supported music files.
Supported audio: MP3, WMA, WAV and FLAC. Use one audio source at a time.
USB music port · Up to 64GBBASS button: Press the red BASS button during playback to switch between b1 bass enhancement and b0 normal sound.
03 / Know your controls
Music and calls.
A few simple moves.
The five-way phone control and the separate Switch button perform different actions.
Voice assistant
Double-press the Switch button to activate or exit your phone’s Siri / Google voice assistant. Availability depends on the connected phone.
Press the phone control
Play or pause music. During an incoming call, press to answer; during a call, press to hang up.
Move left / right
Previous or next track. In FM frequency mode, these movements adjust the frequency instead.
Move up / down
Raise or lower FM3 playback volume.
Hold during an incoming call
Hold the phone button for about 2 seconds to reject the call. During an active call, the same hold switches private-call mode.
04 / Use the right connection
Three ports. Different jobs.
Charging speed depends on your device, cable and supported charging protocol.
PORT 01
Orange USB: QC3.0
For compatible Quick Charge devices. The manual lists output profiles of 3.6–6.5V / 3A, 6.5–9V / 2A and 9–12V / 1.5A.
PORT 02
USB-C: PD 18W
For compatible USB Power Delivery devices. Supports up to 18W using a suitable cable: 5V / 3A, 9V / 2A or 12V / 1.5A.
PORT 03
USB music port: 5V / 1A
Reads your USB flash drive and can provide standard 5V / 1A charging. Use a fast-charge port when charging a compatible phone.
Charging while audio is off: Turning the FM3 off does not necessarily stop its charging ports. They can continue working while the vehicle socket provides power.
05 / Troubleshooting
Less static.
More listening.
Start with the radio frequency, active audio source and Bluetooth connection.
Ask Rexing support →Why do I hear static or another radio station?
Choose a different unused FM frequency and set both the car radio and FM3 to that exact frequency. The manual also suggests reducing the car-speaker volume and raising the phone’s volume to improve the balance.
My phone connects, but I hear no music.
Confirm that the radio is tuned to the same frequency as FM3, select Bluetooth as the FM3 audio source, and start playback on your phone. Check phone, transmitter and radio volume levels.
Which Bluetooth name and PIN should I use?
Select FM3 in your phone’s Bluetooth settings. If a PIN is requested, use 0000. The display shows a steady bt after a successful connection.
Which USB drive and files are supported?
Use a FAT32-formatted USB flash drive, up to 64GB, in the USB music port. Supported formats are MP3, WMA, WAV and FLAC. The QC3.0 and USB-C ports are for charging.
Does music resume automatically?
The manual says FM3 returns to its previous playback mode after restarting. USB music can play automatically; Bluetooth music may need to be started manually on your phone.
Why can’t the other caller hear me?
Answer using the FM3 phone button and check the active call audio route on your phone. Keep the FM3 microphone unobstructed and check call volume. If the problem persists, contact Support.
Why isn’t my phone fast-charging?
Fast charging requires a compatible device, protocol and cable. Use the orange QC3.0 port for supported QC devices or the USB-C PD port for compatible PD devices. The USB music port provides 5V / 1A charging.
Can charging continue when the transmitter is off?
Yes. The manual states that the charging ports can remain active with the FM3 turned off, as long as the vehicle socket is supplying power.
06 / Downloads and help
The right guide for your FM3.
FM3 user manual ↗Pairing, controls & charging · PDFTechnical support →Help with your FM transmitterWarranty & returns →Review current service options
Still need a hand?
Share your phone model, selected FM frequency and the issue.
Register your product ↗Based on the official Rexing FM3 FM Transmitter user manual.