Fuel Level Indicator And Fuel Level Sender - JLG sky trak mmv Service Manual

Electrical System
10.13.19 Fuel Level Indicator and Fuel Level
Sender
The fuel level indicator bars (1) and fuel level indicator
symbol (2) can be found on the left side of the operator's
display panel.
1
2
3
The fuel level indicators (1) work in conjunction with the
fuel level sender (4). The submerged, coil-type fuel send-
er is secured to the fuel tank (5), beneath the cab, and is
connected via the engine wiring harness, bulkhead con-
nector and cab wiring harness to the operator's display
panel.
5
The operator's display panel fuel level indicator bars (1)
illuminate to show the approximate fuel level in 1/4 tank
increments. The fuel level indicator bars will be illuminat-
ed with a low-light green hue, easily apparent for night
visibility and in low-light conditions. When approximately
1/8 tank is reached, the last fuel level indicator bar (3) will
stop illuminating, and the fuel level indicator symbol (2)
will change from green to orange. When the fuel level in-
dicator symbol changes from green to orange, refuel the
tank.
10.168
4
The fuel level sender wiring harness connector can be
accessed from beneath the cab without removing the
cab. The cab must be removed to access the fuel tank
and fuel sender. Refer to Section 3.2.3, b. Cab Removal
in this manual for cab and fuel tank removal instructions.
The fuel level sender (4) consists of a resistance, float-
type fuel level sender mounted in the top of the fuel
tank (5), and the wiring connecting it with the fuel indica-
tors in the operator's display panel.
The resistance of the fuel sender is 33.5 ohms for a full
tank of fuel and 240 ohms for an empty tank. The fuel lev-
el indicator bars in the operator's display panel receive a
signal sensed within the electronic circuitry of the opera-
tor's display panel. Examine the fuel level sender circuit
MM1931
in the appropriate wiring diagram and schematic earlier in
this section.
Battery voltage is applied to the circuit and the circuit di-
vides at the fuel level indicator bars. One path continues
to ground through the operator's display panel and fuel
level indicator connector plug. Another electrical path
goes to ground through the variable resistor of the fuel
level sender.
When the fuel level reaches approximately 1/8 of a tank,
the resistance of the sender increases. This in turn
changes the operator's display panel, causing the green
fuel level indicator bars to turn OFF, and resulting in the
orange fuel indicator symbol (shaped like a standard fuel
pump) to turn ON.
When the tank is more than 1/8 full, the sender resistance
is lower. On the operator's display panel, the green fuel
level indicator bars illuminate according to the amount of
resistance supplied.
a. Fuel Level Indicator Testing
1. With approximately eight gallons (30,4 liters) of fuel
in the fuel tank (5), the bottom fuel level indicator
bar (3) should illuminate, indicating approximately
1/4 tank of fuel.
MM4280
2. The fuel level sender wiring harness connector can
be accessed from beneath the cab without removing
the cab. Beneath the cab, disconnect the fuel level
sender wiring harness connector. Connect a jumper
wire across the two wires in the harness connector.
Model MMV Rev. 12-04