Oil Pressure Sending Unit

TESTING

Gauge Check

1. Detach the oil pressure gauge unit electrical connector.
2. Use a suitable test light (12V–3.4W) to ground the harness side connector.
3. Turn the ignition to the ON position.
4. Check the condition of the test light and gauge as follows:

   Fig. 1: Testing the oil pressure sending unit and gauge

   1. If all components are operating properly, the test light will flash or light steadily and the oil pressure gauge needle will move.
   2. If the test light flashes or lights steadily but the gauge does not move, the gauge must be replaced.
   3. If neither the test light or the gauge operate, check the oil pressure gauge circuit and replace, if necessary.

Sending Unit Check

1. Remove the electrical harness connector from the sending unit and remove the sending unit from the oil filter head.
2. Connect an ohmmeter between the terminal and the sending unit body cavity and check for conductivity. If there is no conductivity, replace the sending unit.
3. Next, insert a very thin wedge through the oil hole in the end of the sending unit. Push the wedge in slightly and measure resistance. There should be no conductivity.
4. If there is conductivity, even when wedge is pushed, replace the sending unit.
5. If there is no conductivity when a 71 psi pressure is placed through the oil hole, the sending unit is operating properly.
6. Check to see that there is no air pressure leakage through the sending unit. If there is air pressure leakage, the diaphragm is broken and the sending unit will require replacement.