Instrument Panel Cluster (IPC) Description and Operation: Hourmeter
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The IPC can display the accumulated engine run time hours using the VF display when the cluster is in the LOCK or ACC position. The IPC stores the accumulated engine run time hours in a non-volatile format. The accumulated hours would not change if the battery was disconnected or removed. When the ignition is OFF and the trip reset switch is pushed in and held for more than 4 seconds, the IPC will display the accumulated hours for 30 seconds. The hourmeter will reset to 0.0 when 10,000 hours are accumulated, and begin to accumulate hours again.