Oil Pressure Warning Light & Sending Unit Test

With ignition in ON, engine off, warning indicator light should come on. Start engine. Warning light should go out indicating oil pressure.
With ignition in ON position, engine off, warning indicator light should come on. If indicator does not come on, remove wiring connector from oil pressure switch terminal and jumper to ground. If indicator now comes on, oil pressure switch is defective or is not properly grounded. If indicator does not come on, light bulb is defective or there is an open circuit in wiring.
If indicator warning light stays on with engine running (with proven oil pressure), disconnect oil pressure sending unit lead wire. If indicator goes out, replace sending unit. If indicator does not go out, repair short in wiring circuit.