Oil Pressure Gauge Inaccurate

Disconnect oil pressure switch/sender connector. Connect one Red lead of Gauge Tester (J-33431-B) to Tan wire at oil pressure switch/sender connector and ground. Set resistance dials to zero ohms, then to 90 ohms.
If oil pressure gauge indicates low pressure, then high pressure, replace oil pressure switch/sender. If oil pressure gauge still does not indicate correctly, locate and repair open circuit in Tan wire between oil pressure switch/sender connector and instrument cluster connector. If wire is okay, replace oil pressure gauge.