Oil Pressure Gauge
Disconnect wire from oil pressure sending unit on engine. Connect one lead of a suitable tester (C-3826) to removed wire and other lead to ground. Place tester knob in "L" position, and turn ignition on. Do not start engine. Oil pressure gauge should read "L" plus or minus 1/8". Turn tester knob to "M" position, oil pressure gauge should advance to 1/2 position on dial. With tester knob in "H" position, gauge should also advance to the "H" position on dial. Should gauge respond to the above tests, but fail to operate when connected to vehicle system, indications are of a defective sending unit.