Know the car before trying to diagnose it
BMW E90 trunk doesn’t operate from switch on Left side kick panel, trunk lid grab handle switch, or from remote key.
Customer was able to open it using mechanical blade key. The latch was also operated using Autologic by going to Body
Then selecting Junction Box Electronics (JBE)
Then go to Component Activations
Now you can select Unlock Rear Lid Lock
No relevant faults were stored.
System operation was reviewed and latch output signal is generated by the JBE.
Inputs from left side kick panel switch and remote key signals go to CAS before being processed by JBE.
The grab handle input goes directly to JBE.
After some head scratching it was discovered that the car has a “Hotel” switch in the glove box to help secure the contents of the trunk when the keys are handed off to a valet or garage attendant.
After de-selecting the lock position, the trunk release worked fine.