03 E46 M3 issues, no obd2, no cluster, keys won't lock

[0-60inM3]

Hello, I am looking for some assistance please, perhaps someone has experienced some of these issues and solved the problems. After both airbags were replaced at the dealer the alarm stated going off while driving.
I had the yellow brake/dsc light come on and would go off after restart.
We lost communication with the OBDII at the indy shop, only communicated with ECU. We have tried numerous scanners along with ista, inpa and nothing works.
I have the following issues: no chime for open door, interior lights flashing while car is running, lost the instrument cluster (nothing is working), random no start, a humming noise is present behind the dash, wipers stop in 3 spots, one key locks occasionally but will not start the car, the other key starts the car but will not power lock/unlock.
Replaced the ignition switch, new key batteries (tried to pair keys to car, no success), new agm rear battery, car starts now but still have all other issues and no yellow brake/dsc lights have come on lately.
I have checked the 50 amp fuse and all other fuses without any luck. I am completely stumped, checked repeatedly on forums/online and trying to repair on my own on a budget. Any help would be most appreciated, thank you!

[Bry5on]

You might have a shorted device on the k-bus. Try unplugging things like the cluster, LKM, GM5, etc one at a time and recheck the scanner each time. If you start getting responses, you found your dead module bringing down the k-bus. Replace it, unless you’re an EE and you like troubleshooting PCBAs

edit: also look for a pinched or shorted k-bus wire wherever the work was performed. It’s possible a wire short is also bringing the bus down.

[0-60inM3]

Thank you very much, greatly appreciated Bry5on 😃. Excellent advice!