IBM Power System Series Manual page 262

Figure 211: Removing the service access cover
7. To activate the identify LED for the faulty part, press and hold push-button (A) on the trusted platform
module card as shown in the following figure.
Verify that the green LED (B) is lit, which indicates that sufficient power exists for the identify LED. If
the LED (B) is not lit, use the location code to find the physical location by using the service label.
258 Power Systems: Temple's Zeppelin procedures for install, remove, replace