Instrument Panel Cluster (IPC) Description and Operation: Voltmeter
WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
The voltmeter displays the vehicle system voltage level. The IPC uses the ignition 1 voltage circuit in order to display a voltage level on the voltmeter.