RAM 2500 Truck 2WD L6-359 5.9L DSL Turbo VIN D FI (1997)
Oil Pressure Warning Lamp/Indicator: Description and Operation
SYSTEM OPERATION
The low oil pressure warning lamp gives an indication when the engine oil pressure is low. The lamp lights with the ignition switch in the On
position and the engine not running as a bulb test. The lamp should be off when the engine is running.
Battery voltage is supplied to one side of the indicator bulb when the ignition switch is turned to the On position. The warming lamp side of the
combination oil pressure switch/sending unit resistor coil is connected to the other side of the bulb.
When normal engine oil pressure is applied to the sending unit, resistance to ground on the warning lamp side of the resistor coil is high and the
lamp goes off. When the engine oil pressure is too low, resistance to ground on the warning lamp side of the resistor coil is low, which causes the
bulb to light.
CIRCUIT OPERATION
The case grounded oil pressure sensor is a variable resistor that connects to circuits G60 and G6. Circuit G60 connects to the oil pressure gauge.
Circuit G6 connects to the oil pressure warning lamp.
Circuit F14 connects to the instrument cluster and supplies battery voltage to oil pressure lamp.
When the oil pressure is below a predetermined level the engine oil pressure sensor completes a path to ground causing the lamp to illuminate.
