Still plugging away on this old problem.
It took some time, but i've got into the service password. Have found that the armrest switch is not switching from open to closed when the armrest is lowered and locked.
The two wires that go into the MLM card from the armrest switch are 501 and 122. with the switch open, wire 501 has 5 volts when the magnet is placed next to the switch, the switch closes and the 5 volts goes to 0 volts, but the display does not indicate this. I still think this can be a CAN bus issue.
Also can not determine the exact location of the termination resistors CRP49 and CRP78.