Advertisement
INSTRUMENTS
8-69
I
I
I
1 0
negative post to the fuel gauge case (ground).
Connect the negative lead of a voltmeter to the
battery negative post. Touch the positive lead of the
voltmeter to the "I" terminal of the fuel gauge. A
reading of 12 volts should be shown on the voltmeter.
Touch the positive lead of the voltmeter to the "A"
terminal of the fuel gauge. A fluctuating reading be-
tween
0
and
7
volts should be shown on the voltme-
ter.
The same fluctuating reading should be shown at
the
"S"
terminal of the fuel gauge. Any other read-
ings indicate the voltage limiter is not functioning
properly and the fuel gauge should be replaced.
FUEL LEVEL INDICATING SYSTEM
(Figs. 1
and
2)
Turning the ignition key on, connects the system
to the battery or charging system voltage. The func-
tion of the voltage limiter is to regulate this input
voltage from the battery or charging system to a con-
stant voltage of approximately
5
volts D.C.
The effect of this constant voltage supply is to
cause the balance of the system to be sensitive to
changes in the valve of resistance at the tank unit
only.
A float arm is hinged to allow the float to raise or
lower dependent on the fuel level. The float connects
to a variable resistance that provides a change in the
resistance with any up or down movement of the float
through
a
wiping contact in the gauge body.
When the fuel level is low or
if
the fuel tank is
empty, the resistance is increased which decreases
the current flow and consequently positions the in-
strument panel gauge pointer to low or empty.
When the tank is full, the float level is at the top,
the minimum resistance is in the circuit and the flow
of current in the circuit is high. The instrument panel
gauge pointer will be moved across the dial to indi-
cate a full tank.
FROM SENDING UNIT
\BULKHEAD
CONNECTOR
I
12 VOLT
INPUT
5 VOLTS TO GAUGES
A()
FROM SENDING UNIT
"BULKHEAD
CONNECTOR
i
O A
so
(ON DASH PANEL)
64
x
418
Fig. J-Fuel
Level Indicating System-
Models A V - I , AV-2, AR-I and AR-2
12 VOLT INPUT
I
,
I
I
O A
I
5 VOLT OUT
TO GAUGES
Testing Fuel Indicating System in
the Vehicle
Raise the vehicle on a lift. Disconnect the terminal
from the tank unit. Attach one lead of the Gauge
Tester (C-3826) to the disconnected terminal. Connect
the other lead of the tester to a good ground.
With the ignition switch turned
on
and gauge test-
er in the
"L" position, the fuel gauge should show
"E" or minus
3/32
inch.
NOTE:
This tolerance permits a small reserve of
fuel at the
"E"
position.
With the gauge tester in the
"M"
position, the fuel
gauge should slowly advance to the
3 4 - 2
position, plus
or minus
inch. With the gauge tester in the
"H"
position the fuel gauge should advance to "F," plus
or minus
3/32
inch.
Should the gauge fail to respond to the above
tests,
indications are of possible loose connections, broken
f
TO BATTERY
TO
BATTERY
1 NEGATIVE POST
POSITIVE POST
FUEL
GAUGE
GROUND
TO IGNITION
INPUT TERMINAL
Fig. 3-resting
Fuel Gauge-
Models AV-J and AV-2
Hide quick links:
Advertisement
