Switch Test; Engine Oil Pressure Switch Test; Field Test - Jacobsen HR5111 Service And Repair Instructions

ELECTRICAL SYSTEM

ENGINE OIL PRESSURE SWITCH TEST

(See Figure 10G-20)
The engine oil pressure switch is a normally CLOSED
(NC) switch. When the ignition key is turned ON the
engine oil pressure light comes on. When the engine
is started and oil pressure increases above 10 psi, the
switch OPENS and the engine oil pressure light goes
OFF.

FIELD TEST

Engine oil pressure light does not come on when igni-
tion switch is turned ON.
Using a jumper wire, ground the switch terminal.
•
Light comes on, proceed with switch test, Step 1.
•
Light does not come on, check circuit wiring and/or
bulb.
Engine oil pressure light does not go off when engine
is started.
SECTION 10G. SWITCHES
Figure 10G-20. Engine Oil Pressure Switch Test
10G-20
Remove BLU wire from switch terminal.
•
Light goes off, proceed with switch test, Step 1.
•
Light does not go off, check circuit wiring for ground.

SWITCH TEST

1. Set multimeter to 200
2. Connect test leads as shown.
•
There should be no continuity and the meter
should read 0–0.5 Ω (ohms).
3. Increase pressure above 10 psi.
•
Switch contacts should close.
NOTE
If switch tests okay and the engine oil pressure
light still does not go out, engine oil pressure
may be too low.
Replace a switch that does not meet all the above
test results or has resistance of 0.5 Ω (ohms) or more.
Ω (ohms) scale.