The steering control unit is actually the clock spring in the middle of the steering wheel. There are different revisions of the clock spring depending on car specification. If the wrong version was fitted that could explain why the functions didn’t work. It could also have been a coding issue, the modules need to be coded for the features fitted to the car.
Sadly most dealers have no clue when it comes to coding modules and simply avoid it unless exchanging old faulty modules for new where there “guided fault finding” process transfers the coding.
The buttons on the wheel work on a bus system. If shift up works but shift down doesn’t it’s likely to be the cable on the switch or the switch itself. There are very small connectors linking the shift buttons to the back of the controls on the front of the wheel. The downshift cable may have been disconnected. You should have the car scanned for faults it’s a tool such as VCDS from RossTech. You can read fault codes and test the switches without taking anything apart.
Finally the Lane assist, if you turn this on and the system is faulty you will see a range of possible messages with more details. Do you see the amber light in the cluster when it’s on?
Sadly most dealers have no clue when it comes to coding modules and simply avoid it unless exchanging old faulty modules for new where there “guided fault finding” process transfers the coding.
The buttons on the wheel work on a bus system. If shift up works but shift down doesn’t it’s likely to be the cable on the switch or the switch itself. There are very small connectors linking the shift buttons to the back of the controls on the front of the wheel. The downshift cable may have been disconnected. You should have the car scanned for faults it’s a tool such as VCDS from RossTech. You can read fault codes and test the switches without taking anything apart.
Finally the Lane assist, if you turn this on and the system is faulty you will see a range of possible messages with more details. Do you see the amber light in the cluster when it’s on?