I have a service light with wrench - what does.

That is triggered by the Body Control Module.

SERVICE VEHICLE SOON
The IPC illuminates the service vehicle soon indicator during any of the following conditions:

The BCM detects a PASSLock failure. The BCM sends a class 2 message to the IPC requesting illumination.
The BCM detects a malfunction in the passive trunk release system. The BCM sends a class 2 message to the IPC requesting illumination.
The BCM detects a failure in the traction control system. The BCM sends a class 2 message to the IPC requesting illumination.
The IPC detects a mismatch between its part number and the vehicle platform configuration sent by the BCM via a class 2 message.