I bought a loom from Braybrooks and fitted it a few weeks ago April 2023.It does not now require T connectors or soldering.It is a plug in item so on my car (AMG C63 W205) the plug goes into the back of the switch above the dash light switch.Red/white, brown and yellow wires.Braybrooks colours are red, brown and yellow .The plug that is removed from the socket is then plugged into the new Braybrooks loom.I have written detailed instructions but not annotated photos yet, but you are welcome to them as add in some tips.
Here is photo of plug in question from behind dash by light switch.You can’t get the data card updated and the car recoded by Mercedes unless you buy new parts from them.I bought used console with clock and swapped out all controls from my car (except the one housing the clock and the air bag light).All seems to work fine.The clock integrates with the digital clock in the car automatically and sets itself - bit scary how complex these cars are.
It’s a fiddly job so just need to go slowly and not rush it.