1996 GMC C3500 AMP GAUGE/TACK

Gas or Diesel?
This is for Gas:
TACHOMETER TEST Tachometer Does Not Function 1. Disconnect IPC connector. Disconnect ignition coil connector. Connect self-powered test light between IPC printed circuit connector terminal No. 6 (White wire) and ground. If test light does not come on, go to next step. If test light does come on, repair short to ground in White wire. 2. Connect test light between IPC connector terminal No. 6 (White wire) and ignition coil connector terminal "B" (White wire). If test light comes on, replace IPC. If test light does not come on, repair open circuit in White wire. NOTE: Before performing following test, ensure Distributor Ignition (DI) system is operating correctly.
VOLTMETER Voltmeter Inaccurate Turn ignition on. Connect voltmeter between positive and negative battery terminals. If voltage reading is about the same as vehicle's voltmeter, voltmeter is okay. If voltage reading is different from vehicle's voltmeter, check gauge circuit. If circuit is okay, replace voltmeter.