Holiday Neptune 2004, Owner'S Manual

Page: 399 / 416

CHASSIS INFORMATION --- SECTION 10 • 399
NEPTUNE 2004
10
The Centroid fuel sender has no moving parts. It works by measuring capacitance,
an electrical property, between its inner and outer tubes in the tank. The more fuel
between the tubes, the higher the reading. Electronics in the hockey-puck head of
the sender convert the capacitance to current to drive the fuel gauge.
Connections:
The Centroid sender has four connections:
• Positive and Negative: Battery voltage to run the electronics in the
sender head.
• Send: Connects to the Send terminal of the gauge on the dash.
• Alarm: Makes a connection internally to the Negative terminal when the low
alarm fuel level is reached (when gauge is reading about 1/8 tank). This turns
on the alarm light on the dash. It is not adjustable.
Checking the Gauge:
• Remove the SEND wire from the Sender. Turn the ignition power ON . The
fuel gauge should read above FULL .
• Touch the SEND wire to the NEGATIVE terminal of the sender. When the
ignition Power is applied, the gauge should read EMPTY .
• If this test passes, place the send wire back on the SEND terminal of the
sender.
Checking the Voltage:
• Place the BLACK lead of the voltmeter on the sender NEGATIVE terminal.
• Place the RED lead of the voltmeter on the POSITIVE terminal of the
sender.
• Reading of the voltmeter should be about 12 Volts DC.
• Place the
RED lead of the voltmeter on the SEND terminal of the sender.
• Reading of the voltmeter will range between Zero and 9 Volts DC.
Calibration and Adjustments:
• Calibration and adjustments to the fuel sender must be performed with the
engine running since this affects the voltage at the sending unit.
There are Two Adjustments on the Centroid Sender:
• Empty: Adjusts for length of sender, should be sealed with a brown sealant,
stating that the sending unit is factory adjusted. If the sealant has been
tampered with, the sending unit may have an incorrect calibration. Do not
change if the sealant is intact.
• Full Adjustment: The full adjustment can be used to correct for slight
differences between fuel meters. During installation, it has been calibrated
for your meter and should not need readjustment.
FUEL SENDING
UNIT