I own a basic VW Caddy MK3 (2009) which was equipped with a RCD 300 head unit. It did not come with the aux function/connectivity and this post explains how I added Bluetooth connectivity. This was a very simple installation with no requirement for VCDS coding; the Bluetooth adapter replicates a CD changer.

RCD 300 bluetooth adapter. At the time of writing this article, I was able to purchase this adapter on Amazon UK for ~£35 – https://amazon.co.uk/gp/product/B0773P8HM5


The installation for this Bluetooth adaptation is a relatively simple one and require very few tools. The manufacturer of the adapter also includes a QR code linking to a easy to follow YouTube video:

Installation steps:

  1. Remove the surround trim with a trim tool or plastic implement – a screwdriver may leave marks on the plastic trim.
  2. Remove 4 T20 screws around the RCD 300 head unit, then pull the RCD 300 out of the dash.
  3. Clip the Bluetooth adapter’s white block connector into the bottom left of the block connector (when looking at the back of the head unit).
  4. Unscrew the small torx screw on the back of the RCD 300 then screw back in with the small grounding connector between the screw head and the back of the head unit.
  5. Plug in the optional microphone and route this to an appropriate position in the vehicle.
  6. Reverse the removal steps to secure the head unit and trim in place.

RCD 300 bluetooth - Close-up plug The 12 pin VAG connector Using the adapter with the RCD300

Once installed, you need to switch the RCD300 to CD mode – press the CD button. Whilst you can still use the unit as a CD player, please remove any CDs before proceeding with these instructions.

Once in CD mode, search for available Bluetooth devices on your phone and connect to the available device. Once paired, the RCD 300 should replicate the connection of a CD multi-changer. Tracks on your phone show up as CDs, therefore you can skip tracks with the left and right arrow buttons. These two buttons also control accepting or rejecting incoming calls on the phone. If your vehicle has corresponding steering wheel controls, these will carry out the same functions.

From there onwards, your phone will auto-connect to the Bluetooth device which becomes available after the vehicle ignition is enabled (and the head unit is powered on). I have found that because of the slight delay – 2 seconds – between the device powering on and connecting to the phone, the RCD 300 defaults back to FM/AM, so it is a requirement to press the CD button every time.

RCD 300 bluetooth - playing spotify Playing Spotify over bluetooth from my grubby phone!