Installed check
Turn off the engine. Disconnect the wire from the oil pressure switch.
Connect an ohmmeter between the oil pressure switch contact and the engine block. The resistance must be 0 0m.
Start the engine and leave it to idle. The instrument should show ∞.
If one of the two measurements does not measure the required value, the oil pressure switch must be replaced. If both measurements are normal, check the electrical wire going to the test lamp, see point 23.1.
Connect the wire to the oil pressure switch.
Checking the removed oil pressure switch
Connect an ohmmeter between the contact and the oil pressure switch housing. The resistance should be 0 ohm. Otherwise, replace the switch.
Insert a thin needle into the oil hole of the switch and press lightly. The instrument should show ∞. Otherwise, replace the switch.
Using an air pump, set a pressure of 0.5 bar at the oil hole of the switch. The resistance should be 0 ohm. In this test, care must be taken to ensure that air escapes. If this is not done, the switch membrane will be damaged. Replace leaky valve.