Vehicles over a decade old feature basic stereos with zero external connectivity. Instead of overhauling the head unit, you can use an auxiliary cable for car cigarette lighter to connect to the AM/FM stereo.
Although it might have sound quality issues, this option is cheaper and easier to install than replacing the head unit. Here’s how it works.
Table of Contents
- What Is an Auxiliary Cable?
- Auxiliary Cable Types in the Market
- Advantages of Using Car Cigarette Lighter Aux Cable Connections
- Typical Auxiliary Cable for Car Cigarette Lighter Issues
- Alternative Car Stereo Connectivity Options to the Cigarette Lighter Aux
- Wrap Up
What Is an Auxiliary Cable?
An auxiliary cable is a cord with 3.5mm headphone jacks on both ends for connecting your phone, tablet, or MP3 player to another device with the same port.
In this case, the device with the aux port is the FM radio/Bluetooth transmitter that plugs into the cigarette lighter power outlet.
Although originally designed to power the electrically heated cigarette lighter, this port has become the de facto DC connector for powering automobile accessories.

A set of AUX cables with 3.5mm TRS headphone jacks
So, if your vehicle lacks an advanced head unit, you can use the dashboard cigarette lighter port to hold and power an FM radio/Bluetooth transmitter.
This device features an AUX port that receives the audio signals from your device and then compresses these signals for transmission via Bluetooth or FM.
If your stereo features Bluetooth, you can pair the two devices to play music via your mobile device.
But if it only has AM/FM reception, you can adjust the car cigarette lighter device to broadcast at a specific frequency. After that, set the stereo to this frequency.
Once connected, the radio will play your phone’s audio files as if receiving waves from a radio station.
Auxiliary Cable Types in the Market
These cable types fall into two categories: 3.5mm plug structure and cable structure.
3.5mm Plug Structure
Considering the 3.5mm plug, they come in either of these three types.
TS (Tip-Sleeve)
Also known as a mono-mini, this auxiliary cable jack features 3.5mm connectors with a tip for the mono channel and a sleeve for the ground connection.
The typical application for this TS cable is to provide 12-volt trigger connections between audio components.

A TS jack
TRS (Tip-Ring-Sleeve)
Most aux cables feature these stereo mini connectors, where the tip powers the left channel while the ring handles the right channel. The sleeve provides grounding like with the TS type.
TRRS (Tip-Ring-Ring-Sleeve)
This aux cable contains connectors with four sections. The tip powers the left channel, while the front and rear rings run the right channel and grounding.
Lastly, the sleeve runs the microphone, meaning this aux cable is a must-have if the connection requires mic connectivity.

A 3.5mm TRRS jack
Cable Structure
Aux cables can have the following structures.
Coiled Cable
These wires have a coil design that allows the cable to flex and extend to your phone or MP3 player without excessive tangling.

A cigarette lighter adapter with a coiled cable
Flat Cable
Instead of having a round audio cable, this wire has a flat, ribbon-like design that is better at preventing tangling.
Right-Angled Cable
Instead of having connectors that plug in straight to the AUX port, these cables feature right-angled connectors.
Depending on the cigarette lighter port location and transmitter size, this design can provide a convenient, low-profile design.
Advantages of Using Car Cigarette Lighter Aux Cable Connections
- Easy installation: Using the cigarette lighter audio transmitter option is easier than replacing the head unit to accommodate your aux cable. It is cheaper, as well.
- Universal integration with car stereos: All cars feature a cigarette lighter port that also functions as a 12V auxiliary power outlet. Therefore, using an aux cable for a car cigarette lighter is a universal fix.
- Minimal cable clutter: Placing the aux cable and phone at the cigarette lighter port level eliminates clutter on the upper dashboard level where the head unit sits.
- Charging ports: The cigarette lighter transmitter usually features one or two USB charging ports. Therefore, you can connect your phone via the aux cable to play audio and use the USB wire to keep it charged.

A cigarette lighter charging adapter with two USB ports
Typical Auxiliary Cable for Car Cigarette Lighter Issues
Although convenient, this auxiliary power socket connection has its challenges. The typical ones include the following.
Poor Audio Quality
This cigarette lighter transmission option might not deliver the best audio quality because of static or distortion.
Interference from other car electronics can inject noise into the wireless Bluetooth or FM transmission on the way to the radio.
There’s also the sound compression issue and Bluetooth audio sampling. These factors can distort the sound slightly compared to the original file playing from your phone.
But in some cases, the issue might be dirty or corroded 3.5mm aux connectors. Replacing or cleaning the plugs or ports can solve the issue.

A cigarette lighter adapter with a hands-free call feature
No Audio Output
If the stereo fails to pump sound out through the speakers, look at the aux cable. The electrical connection might be faulty, loose, or improperly connected.
Also, the cigarette lighter port might have issues, but you can troubleshoot this fault by checking if the transmitter turns on.
Incompatibility
Although widely compatible with most devices, the transmitter might be unable to decode the audio files in your phone. Try to update its software or change the file format of the audio files.
Overheating
The cigarette lighter port or transmitter can overheat if you draw too much power from the socket. Also, a faulty adapter/transmitter or lighter socket can cause this heating issue.
Alternative Car Stereo Connectivity Options to the Cigarette Lighter Aux
If the cigarette lighter option does not work, try these affordable solutions before going the radio replacement way.
Cassette Tape Adapter
These cassette adapters are unique because they are aux-to-tape devices with transmitting heads and mechanisms that simulate tape movement.
The head converts the audio input to a magnetic signal for the tape deck’s reading head to interpret and play. Try this option if the head unit features a cassette tape player.

A cassette tape adapter
USB input
If your stereo has a USB connection, it is relatively new. This connection will provide better audio quality when you connect a USB device, such as a USB flash drive. If advanced, you can use wired Android Auto or Apple Carplay.
SD card
Loading SD cards with audio files can be tricky, but they will deliver better audio quality than the cigarette lighter transmitter.
Wrap Up
If you’re on a budget and want to upgrade your car stereo, this cigarette lighter auxiliary cable option is your best bet.
But ultimately, replacing the head unit is the best option to give you multiple connectivity options.
We can recommend the best of both options, depending on your preference. Contact us for further information.