Service Manual

Engine Oil Pressure Switch
The switch is normally closed (NC) and opens with
pressure.
The switch opens at approximately 8 psi.
1. Turn ignition key switch ON. Oil pressure lamp should
be
on.
If bulb is not on:
1. Disconnect wire from switch and touch wire to a good
gr
ound.
2. If lamp comes on, replace switch.
3. If lamp does not come on check lamp and/or wiring
be
tween lamp and switch for continuity.
If lamp is on with engine running:
1. Shut off engine immediately.
2. Check switch by disconnecting wire. Light should
go
out.
3. If light is still on, check for short circuit in wiring.
4. Install test gauge in engine oil pressure switch port.
S
tart engine and check for 30 psi minimum at 1500 rpm.
If engine pressure is good, replace switch. If engine
pressure is low, DO NOT operate the engine.
1
Figure 26
1. Engine oil pressure switch
Liquid Cooled Diesel Engine Page 4 - 26 Workman 3300-D/4300-D