So I was stuck in stationary traffic today with a friend in the car. I was talking about the air suspension and pressed the up button for it to lift. Instead of lifting the lights just sat there flashing with no movement at all.
A few moments later I noticed a burning plastic smell which was really strong and was causing my eyes to water. I thought maybe something to do with the air suspension had burned out or something was touching the engine/exhaust. After about 5 or 10 minutes the smell went away and an ABS fault message popped up.
I plugged the Nanocom in which reported "Brake switch failure". I took the brake light switch out and here's what I found:
It makes sense now why it didn't lift as it obviously thought the brakes were being pressed!