Cars manufactured 2009 or before may experience battery drainage issues when installing the RCD330. Their steering wheel buttons will also not work with the RCD330. This is where this cable comes to help. It will solve any battery drainage issue and will allow your steering wheel buttons to work with the RCD330.
This cable is needed if:
1. Your car is 2009 or earlier (2005-2009 Cars)
2. You have a 8 button Multi-Function Steering Wheel
This cable is NOT needed if:
1. Your car is 2010 or newer
2. You have a 12 button Multi-Function Steering Wheel
If in doubt of whether or not you need this, please send a message, and i'll reply to you the same day.
This will not solve ALL cases of battery drainage. There is a small chance (1 in 100) that your CANBUS Gateway is incompatible with the Simulator, in which case you'll need to upgrade your gateway to a post-2010 model. However for the general majority, this will do the trick.