Jacobsen HR 5111, Service And Repair Instructions

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HYDRAULIC CHARGE PRESSURE
SWITCH TEST (See Figure 10G-17)
The charge pressure switch is a normally CLOSED
(NC) switch. When the ignition key is turned ON the
hydraulic charge pressure light comes ON. When the
engine is started and hydraulic charge pressure in-
creases to 118–132 psi, the switch OPENS and the hy-
draulic charge pressure light goes OFF.
FIELD TEST
Hydraulic charge pressure light does not come on
when ignition switch is turned ON.
At the switch, disconnect the plug. Using a jumper wire,
jump across the contacts of the plug.
•
Light comes on, proceed with switch test, Step 1.
•
Light does not come on, check circuit wiring and/or
bulb.
Hydraulic charge pressure light does not go off when
engine is started.
At the switch, disconnect the plug.
•
Light goes off, proceed with switch test, Step 1.
•
Light does not go off, check circuit wiring ground.
SWITCH TEST
1. Set multimeter to 200 Ω (ohms) scale.
2. Connect test leads as shown.
•
There should be continuity and the meter should
read 0–0.5
Ω (ohms).
3. Increase pressure to 118–132 psi.
•
Switch contacts should open.
NOTE
If switch tests okay and the hydraulic charge pres-
sure light still does not go out, hydraulic system
charge 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.
ELECTRICAL SYSTEM
SECTION 10G. SWITCHES
10G-17
10G
Figure 10G-17. Hydraulic Charge Pressure Switch Test