How to Add Bluetooth to Car Factory Stereo

Bluetooth connection allows you to connect two devices and enable communication between them without any wire or cord.

It is usually seen in hands-free earpieces for mobile phones or wireless loudspeaker systems like The JVC KW-R925BTS. Bluetooth stereo is common in new cars, but if your stereo is an old one, you might not broadcast audio through it.

How to add bluetooth to car factory stereo
Photo Credit: Jackson David,

Your car may have an AUX input that connects each audio source through the 3.5mm mini-jack. Older cars can even accommodate cassette adapters.

However, these solutions contribute significantly to the interior and they are cheap ways to integrate wireless audio into any car without adding ugly cables or changing the outlook of the audio system.

Bluetooth in Cars

Integrating the Bluetooth feature in your car radio will give you the opportunity to hear your caller’s voice through the car speakers while driving.

You can also view incoming call notifications on the stereo screen and possibly send audio from the device down to your car stereo. Most universal Bluetooth adapters do not require connection with the car radio.

It is important that you keep an eye on the road while you put your hand on the steering wheel when talking to your callers. With Bluetooth devices, you can also stream songs from your tablet, smartphone or other Bluetooth devices to the car radio.

Buy this JVC KW-R920BTS Built-in Bluetooth audio player

There are 3 Ways to Make Use of Bluetooth in the Car

(i) Universal Bluetooth kit functional in every car

(ii) A car-specific Bluetooth adapter which connects directly to the radio

(iii) A new car stereo system with integrated or additional Bluetooth functions

Universal Bluetooth Kit

Universal Bluetooth kit works in almost every vehicle. Some of these are stand-alone, simple devices with small speakers and microphones like what you find in The JVC KW-R925BTS.

They are usually connected to your sensor or mounted on the dashboard and do not interfere with the vehicle radio at all. This is good because it is movable from one car to another although its use is limited for hands-free calls.

Other Bluetooth car adapters are connected to the stereo so music is muted when a call comes in. Also, when calls are made, they are played through the car speakers, not from small standalone speakers.

Some of the kits handle online music streaming although you need to detach the car radio and disconnect several cables to fix the kit. It takes a little effort though, but the results are worth it.

Car-Specific Bluetooth Car Adapter

This adapter is the interface that is connected to the car factory stereo system.

During installation, the cable connecting the factory radio to the car wiring is usually disconnected. The connection houses to the stereo cable while the microphone is installed for hands-free calls.

Caller information is displayed on the stereo screen and you can answer and make calls using stereo controls. A connected microphone hangs on an umbrella or is mounted somewhere in the dashboard, and you hear the caller through the car stereo speaker.

This is the best option if you intend to save the factory stereo. Although installation work is required, you get a Bluetooth setup that is fully integrated into your stereo for free phone calls.

Many of the new systems can also process music streaming. Notably, USA Spec has developed a Bluetooth integration package for selected Acura and Honda vehicles.

Aftermarket Stereo System with Integrated or Additional Bluetooth Functions

The final way to add Bluetooth to the vehicle is to fix a car stereo equipped with Bluetooth function or offer an adapter. Depending on your chosen stereo system, you can easily control many functions of the smartphone and streaming of music.

How to add bluetooth to car factory stereo
Photo Credit: Ian L,

If you choose a stereo with integrated Bluetooth, you do not need to install a separate storage adapter box. The JVC KW-R925BTS has an inbuilt Bluetooth for free calls and streaming of music.

Because of the popularity of Bluetooth, it is found in a growing number of new stereo systems. This means you don’t need to buy a costly stereo to enjoy wireless technology.

If you are buying a car stereo, look for a stereo with inbuilt Bluetooth functionality. Adding Bluetooth to the car radio can be less stressful.

At the least, Bluetooth connection makes it safer, easier and – in more countries – legal to handle your phone in a car. With the expansion of applications used in Bluetooth technology, it is becoming useful in cars.

How to Install Bluetooth Audio

The General concept is easy, so you need to feel comfortable removing the interior parts and working right under the dashboard.

Now, follow these procedures.

Detach the Stereo

Take apart the necessary pads and pull the stereo system from the installation point to reveal the back of the device. This might require a special stereo eraser. For more information, see your vehicle maintenance manual or online forum.

Take a snapshot of the entire process to enable you assemble them in the right order when you are through.

Connecting the Modulator

Disconnect the antenna wire. Now plug the wire into the radio antenna and the car antenna wire into the FM modulator. Check to see if there is a frequency selector in the FM modulator and select the best frequency.

This has to be the one with the lowest interference.

Some cars (like Nissan models and GM that appeared in the market in the 1980s and many others in contemporary market today) used indecent antenna connectors in factory radios in place of typical Motorola connectors.

If you experience this with your car, you might need to get an antenna connector.

Find Power Source

Use a circuit test or voltmeter to search for cables that contain juice when you switch on the ignition and subsequently go off when the switch is turned off.  Radio circuits are usually the best choice.

Also, your car manual could be of help or you search the internet for solutions.

Connect the Power Supply

Use the splice connectors to connect the power switch cable provided with the modulator to the stereo power source that you found in the last step.

In the event that the modulator doesn’t have a default fuse, we suggest adding a fuse to the positive cable. Link the ground cable from the stereo FM modulator to a ground connection in the dashboard.

Video: How to add Bluetooth to Your car factory stereo

This video explains how you can add Bluetooth to your car factory stereo

Install the modulator power switch properly in a suitable location close to the radio or console.

Plug the Audio Cable Connector into the Stereo FM Modulator

Make the connection with 3.5 mm plugs in one place in the glove box, in the console or in another place that is easily accessible but hidden. Fasten the FM under the dashboard with cable ties. Gather loose cables with additional cable ties.

Ensure it is not too tight to prevent the crimping of the cable.

Audio Test

Turn on the ignition, activate the FM and connect the audio to 3.5 mm jack. Set the radio to the FM modulator frequency and ensure you get an audio signal.

Adding Bluetooth

Remove the test connection and charge the Bluetooth adapter to enable you to connect it to your MP3 player, tablet or smartphone. Connect the 3.5mm plug to your Bluetooth adapter. You can now turn on audio through the Bluetooth radio.

Bonus Step

Connect the USB car charger to the power source that you use in the “Power connection” and always keep your Bluetooth adapter connected. To do this, the USB car charger must be disassembled and the cable must be soldered to the charger circuit.

If you are not ready to do so, keep a good charger in your car and charge your Bluetooth adapter if necessary – that is what we do.

Replace the Panel

Remove all covers to get access to the radio. Congratulations – You can now stream audio with Bluetooth.

If you try all these steps and still find it difficult to connect your stereo, then you can contact a technician. See also, the best car stereo for your car here.

To get the best audio and Bluetooth experience, we recommend The JVC KW-R925BTS.