Retrofitting Bluetooth & Wireless Charging to an Audi TT Mk1 (Stock Radio)

by Felix Wong | 17 Dec 2023

Owning a now-classic car like the first-generation Audi TT Roadster comes with its charms and challenges. While it may lack modern amenities like Bluetooth connectivity and wireless charging, with a bit of ingenuity and effort, it’s possible to bring some of these conveniences to older vehicles.

Here’s how I retrofitted Bluetooth and wireless charging to Teeter, my beloved Audi TT, along with a rundown of how well the upgrades have performed.

Parts List

I bought all the parts below from Amazon except for the vent mount. The prices below are what I paid for them, excluding sales tax and shipping unless noted.

1. RoundMount vent mount for Audi TT Mk1 ($44, including shipping from Poland that took five weeks). A viable alternative would be the Clearmounts phone holder for Audi TT available on Amazon. However, the mount doesn’t look quite as good and the phone would sit nearly two inches lower.
2. Apple Magsafe wireless charger ($30)
3. Jie Rui BT-5908 Bluetooth 5.0 Adapter with 2 RCA inputs and external microphone. ($17)
4. 30W USB-C/USB-A 2-port car charger. ($9 for a 2 pack)
5. Cigarette lighter socket ($7)
6. 3.5mm female to dual RCA female splitter ($8)
7. SPST lighted rocker switch ($6 for six)
8. Kable Control zip tie mounts ($12 for 100 pieces)
9. T Tap wire connectors ($6 for 60 pieces)

The total cost of the above is $139 plus state sales tax and shipping.

I already had a Phillips cassette adapter ($5 on ebay) which I used for an auxiliary input to the radio. I’ve used it reliably for the last 10 years, with good sound.

A better Aux-In solution would be using the CD changer input—instead of using the tape player—with an adapter. I believe that the Grom Audio AUDA1 AUX cable input car stereo kit would work. But it costs $97—significantly more than the humble cassette adapter.

It should be noted that I also used zip ties, a couple of wires, and 3M VHB tape for this project. But I already had those.

Procedure

Below is an overview of the steps I did to perform this retrofit.

1. Adding Aux-In to the Stock Radio: I opted to integrate an AUX-in functionality to the stock radio using a Philips tape adapter. By rerouting the cable through the rear of the radio and carefully reassembling it, I achieved a neater appearance while preserving functionality.

   

2. Installing Vent Mount and Wireless Charger: After acquiring a vent mount from RoundMount, I removed the magnets from its swivel mount and attached an Apple MagSafe wireless charger using 3M VHB (Very High Bond) tape. Despite a five-week wait for shipping from Poland, the mount’s high-quality construction and design made it worth the wait.

   

   Installing the mount required removing the center vents, which was achieved without too much difficulty using a flat screwdriver. I covered the screwdriver with electrical tape to avoid marring the vent bezels or the dash.

   

3. Installing the Microphone: I replaced the stock Audi microphone with one included in the Bluetooth module I purchased. This involved removing the instrument cluster, which sounds intimidating but is really quite easy (follow the instructions in this video).

   

   Then I neatly glued the new microphone with silicone adhesive.

   

   I also neatly attached the microphone cable to the rear of the instrument cluster with zip tie mounts and zip ties.
4. Adding USB Adapter and Power Switch: I incorporated a USB adapter and power switch for the MagSafe wireless charger, ensuring a clean installation while keeping the stock cigarette lighter free.

   

   By wiring a second cigarette lighter with a lighted switch, I gained control over the wireless charger’s power supply while keeping the first lighter socket available. The USB adapter—which plugged into the second lighter socket—was rated 30W and could provide 20W to its USB-C port. That is more than enough to power the 15W Magsafe charger.

   

5. Installing the Bluetooth Module: Connecting the microphone and tape adapter’s 3.5mm jack to the Bluetooth module facilitated seamless integration. Since I wanted it to only operate whenever the radio was turned on, I tapped into the radio harness’ ignition-switched 12V (black/blue) and ground (brown) wires to power it.

Video

Below is a video of performing the steps above. It took me approximately five hours. However, I was being very meticulous. I also took a lot of photos and videos for this write-up.

Performance

• Bluetooth Connectivity: Overall, the Bluetooth connection has been quick and reliable, with no signal interruptions.
• Mount and Wireless Charging: The vent mount positions the phone perfectly for easy access while driving, and the Apple MagSafe charger provides strong and efficient wireless charging.
• Issues with Hands-Free Calling: Unfortunately, the Bluetooth module’s hands-free calling feature doesn’t work with my iPhone, necessitating the use of the iPhone’s speakerphone instead. This is a big enough issue that I will probably replace the Bluetooth module with another one someday.
• Audio Quality: Sound quality through the Bluetooth module seems inferior compared to a direct connection through the tape adapter. I have to compensate for reduced bass and treble by changing the equalizer settings on my music player app (VLC)—something I never felt compelled to do before in my Audi TT. It’s adequate, but is another reason to find a better Bluetooth module.
• Switch for Wireless Charger: While the lighted switch for the wireless charger is convenient, its current placement inside the ashtray feels makeshift and I may reposition it for a more polished look in the future. But it’s good enough for now.

Conclusion

In conclusion, retrofitting Bluetooth and wireless charging to my Audi TT Roadster Quattro has enhanced its functionality and convenience, despite some minor drawbacks. With careful planning and execution, it’s possible to bring modern features to classic cars without compromising their original charm, for nominal cost.