I recently purchased a used 2016 GLC and my mechanic and I have been doing the usual maintenance post purchase. the car didnt seem to come with active blind spot assist as the little warning signals were not on the side mirrors, but my mechanic was adamant that it should definitely have that system as it is a 4matic Burmester GLC with pretty much all other features including active brake assist. after rmuch digging, we decided to pull the glass on the side mirrors out and realised they had been replaced with basic cutout mirror glass, and there actually were wires in the side mirror housing for the blind spot asisst to connect to the mirror. he also checked under the back bumper and noticed there is a blind spot sensor on the right side but the sensor on the left side is missing, though the housing and cables are there. so he assumed the left side had probably fallen off in the past and led to a malfunction that the previous owner did not bother to replace. but heres the interesting part. the blind spot assist doesnt show up in the guage cluster menu, neither was the active brake assist showing up as well. we decided to order the missing parts (the left sensor, the two OEM side mirror glass with the BSM warning signals, as well as the front collision sensor for the active brake assist system which was also missing from the front bumper). Today we replaced and installed the two side mirrors, the missing front brake assist sensor and the missing back left blind spot sensor and after fiddling with his OBD system, the active brake assist magically appeared back on the guage cluster menu, but he has not been able to get the blind spot assist to come back as well on the menu. I searched up my VIN on google and did a little digging and found this item "234 BLIND SPOT ASSISTANT" on a VIN checker site for my car, and after googling this as well, I realised this means the Blind spot assistant was retrofitted and didnt necesarily come with the car from factory. so right now my question and dilema I need help solving is, how do we properly code/install the blind spot system into the car and get it to show up on the guage cluster menu so it can start working properly. are there speciifc softwares we need to get so the OBD can install this into the menu so the system begins to work? can anyone assist with this as itll be super helpful!!!

collision prevention popped up after he worked on his OBD, but BSM still not popping up

the replacement mirrors installed today