4 hourmeter, 5 coolant temperature sender, Hourmeter – JLG 723A Service Manual User Manual
Page 144: Coolant temperature sender

Electrical System
9.36
L2906H, 2906H, 3507H, 619A, 723A, 29.6LP, 29.6, 35.7
7. Check the fuel level sender. The resistance of the
fuel level sender are:
8. A defective fuel level sender in the fuel tank may also
prevent the fuel level indicator from moving.
9.14.4
Hourmeter
The hourmeter is a non-repairable instrument that
records hours of machine engine operation in tenth of an
hour increments and is located in the instrument panel.
The hourmeter is an analog device, similar to an
odometer, and will display 99,999.9 hours before
resetting to zero.
If trouble is suspected, time the hourmeter for six minutes
to verify that a tenth of an hour has been recorded.
The hourmeter is built into the instrument panel and
cannot be repaired. If the hourmeter is suspect, replace
the instrument panel.
9.14.5
Coolant Temperature Sender
The coolant temperature sender (2) is located the rear of
the engine below the cylinder head.
a. Coolant Temperature Sender Removal
1. Park the machine on a firm, level surface with the
machine level, retract and level the boom. Place the
transmission control lever in the (N) NEUTRAL
position and engage the parking brake. Shut the
engine OFF.
2. Place a Do Not Operate Tag on both the ignition key
switch and the steering wheel, stating that the
machine should not be operated.
3. Allow the engine and all system fluids to cool.
4. Properly disconnect the battery.
5. Disconnect the wiring connector at the coolant
temperature sender lead.
6. The coolant temperature sender is threaded into the
engine block. Remove the sender.
b. Coolant Temperature Sender Inspection and
Replacement
Inspect the sender and the wiring harness connector
terminals for continuity. Replace a defective or faulty
sender with a new part.
c. Coolant Temperature Sender Installation and
Testing
1. Thread the coolant temperature sender into the
engine housing snugly, then connect the sender
connector to the wiring harness connector.
2. Properly connect the battery.
3. Check for proper fluid level.
4. Check the coolant temperature sender. The
resistance of the coolant temperature sender are:
5. Start the engine, allow it to reach operating
temperature and observe the operator instrument
cluster for warning indication. If the sender is not
defective, the problem could be elsewhere; possibly
in a shorted wire, improper-running engine, improper
or low coolant, obstructed or faulty radiator, coolant
pump, loose fan belt, defective instrument display,
etc.
6. Close and secure the engine cover.
7. Remove the Do Not Operate Tag from the ignition
key switch and the steering wheel.
Fuel Tank
Capacity
L2906H, 2906H,
29.6 & 619A
3507H, 35.7
& 714A
100%
4 ohms
10 ohms
50%
162 ohms
185 ohms
0%
314 ohms
297 ohms
MZ5480
2
Temperature
Resistance (ohms)
130°C (266°F)
28.9 ±1.5
120°C (248°F)
36.8 ±2.2
90°C (194°F)
83.3 ±6.9
60°C (140°F)
222.5 ±22.9
20°C (68°F)
1138.3 ±140.8