When Your Car Has No Aux Port

Attempting to connect a headphone jack to car with only a cigarette lighter and a USB port

I bought a new car in 2020, and while I was test-driving it, I noticed something missing: an auxiliary audio (“aux”) port.

An auxiliary audio port lets you play sound through the car’s sound system from a device (like a phone) with a headphone jack. In my previous car, I was able to play music from my portable music player through the aux port, but not anymore.

My current solution is to use an FM radio transmitter. This takes the audio from a headphone jack and transmits it on the same frequency as an FM radio station, so you can tune the car’s radio to the frequency and listen that way. This works but has some problems:

  • The sound isn’t always clear. I’ve noticed that things in my surroundings can cause interference, especially when I drive through certain areas.
  • The signal could potentially be picked up in nearby cars. Although the signal is supposed to be low power and only transmitted to my own car, I suspect that other cars may be able to pick it up. This is because I’ve been on the receiving end of this, either on the same frequency as an actual radio station or on the same frequency that I’m using for myself.
  • Finding unused frequencies is tedious when traveling long distances. When I reach a new location, I would have to check if the previous frequency I’m using is now being used by a station. The only solution I have for this is to simply not bother using the transmitter at all.

I suppose with the trend of smartphones supporting Bluetooth (and removing headphone jacks!), the preferred method of connecting a device to a car now seems to be Bluetooth, which my new car does support. But my portable music player doesn’t support Bluetooth, so I decided to look for a Bluetooth transmitter.

The annoying thing is that a lot of “Bluetooth transmitters” I found actually receive a Bluetooth audio signal from the source and transmit an FM radio signal. So it solves the problem of using a newer device in an older car, whereas I’m trying to solve the problem of using an older device in a newer car.

Thankfully, I found a device that receives an audio signal from a headphone jack and transmits a Bluetooth signal. This was the Aluratek ABT05F, and it was almost perfect. The only thing was that it didn’t work in my car. I managed to get it to pair (I think) but I never managed to play any sound through my car.

This device is advertised as a transmitter for use with Bluetooth headphones and speakers, and it did work with my Bluetooth speaker. So I suspect that the protocol is different from the protocol that the car uses to communicate with a phone.

Unfortunately, this is the only device I could find that does what I need (aside from a few other similar products from Aluratek, but I suspect they would have the same problem in my car). So I guess I’ll have to stick with the FM radio transmitter for now.

Reply to this post via e-mail or on: Facebook, Twitter.
Philip Chung
Philip Chung
Software Developer