No reversing lights or rear parktronic

[Diydel]

Hi all

2002 Ck230 convertible automatic

Reversing lights and rear parktronic have stopped working. Not a fuse or bulbs, other threads suggest switch in gear shifter unit, on disassembly only find part no A0025421018 which is tiptronic selector module- does this operate reverse lights or is there a separate external switch.

Any suggestions greatly relieved

Thanks