STEP 1. Measure the power supply voltage at engine oil pressure switch connector.
(1) Disconnect the engine oil pressure switch connector measure at the harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal OPSW line and ground.- The voltage should equal battery positive voltage.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 4. Go to Step 2.