Hi everyone I am new to the forum and am looking for some help. I have an A4 cabriolet and the boot unlock from the key fob doesn’t work. The light on the fob works and I changed the mechanism it was about £18. There is no unlock button on the driver door ? Anyone have any suggestions?

thank you 

Could be the boot actuator or the remote fob receiver. Have you tried using the spare key to see if it definitely isn't the main key playing up? 

Also you could look at getting a diagnostic check carried out or get an auto electrician to take a look as it could be a broken wire. 

Also unsure if it would be relevant but has the car got wet carpets? I ask as the comfort control module is under the carpet passenger footwell. If the footwell gets wet and floods the ccm it can cause all kinds of weird electrical issues. 

Thank you for that information! I was reading that there’s a module that controls it. I’ll take a look. I have tried the spare key it’s the same. I could use a diagram or schematic. I’m handy with electrical issues. The old mechanism was very stiff but operated when I put 12 volts on it directly. I wonder where the problem is. 

You're welcome, sorry I can't help more.