Low fuel warning light has stoped working

The light is not due to any clogged filter issue, you have an engine fault in one of the sensors most likely.

if you know there is gas in it sounds like fuel sending unit in tank

The sensor is part of the fuel pump module inside the gas tank.
The signal is sent to the body computer, so it could be a faulty module or a problem with the body computer.
The circuit would need to be checked with a meter.

by the sounds of it sounds like one of 2 lights that light up, the one is indicating that the coolant level is low so this would need checking, if its not low then it may be the next problem im going to tell you about, is the wavey water picture above a tank or below, if the wavey part is above the tank on the warning light then its coolant level, if the coolant level is ok then chances are either the sensor is faulty of the connections are faulty, the level sensor is located in the lid of the coolant filler cap so unplug the connector and plug back in and see if that makes any difference, if not then the sensor needs replacing,

now if the wavey water symbol is below an object on the warning light then this is telling us that the fuel filter has sensed their is water setting in the filter, now this only happens with diesels and usually its a faulty sensor and not that their is water in the fuel, if it is the fuel warning light then most of the time it cant be fixed unless the sensor is changed but even then its no guarantee it will put the light out,

the "sensor" is actually just a long arm with a "floaty? on the end and gauges where in the tank the top of the fuel is located therefore giving you a read out on your dash. the sensor your talking about sounds like the low level readout sensor.this is located elsewhere and is simply asensor that reads the information of of the fuel pump and vocalizes low fuel warning. if you knowingly have fuel in your vehicle then your sensor may be shorting or or your dash gause has a short.

Hello graytape, was the fuel gauge and low fuel light working and then one day just stopped working?, if so, you have probably blown a fuse and you should be able to locate what fuse and where it's located in the owner's manual.
If you recently got the vehicle and then you found out that the gas gauge and low fuel light doesn't work then that is something completely different.
without knowing the year of the vehicle I can only give you an educated guess.
Many vehicles have a float in the gas tank and this float is directly linked to what you see on the gas gauge. However, after a number of years the floats get saturated from the fuel and become heavy, heavy enough to where they don't float anymore. That is one of the most common causes of the fuel gauge not working.
The sensor that activates the low fuel warning light may be independent of the fuel gauge and the fuel in the tank isn't low enough to turn it on. Your tank has to be very low to activate the low fuel warning light.
Good luck!

I have a 1999 Ford Expedition with a 5.4L Engine and don't know what you are talking about. I searched under mileage sensor for the 99 expedition but could only find On-Board Warning Systems.

Are you talking about the Vehicle Speed Sensor?

If so, this is located near or on the transmission and has wires that go into the harness, and basically is a pickup coil that detects movement of the transmission which then controls mileage on the odometer and the speedometer.


On-Board Warning Systems Turn on the ignition switch in almost any vehicle and watch the instrument panel. The modern automobile has an abundance of warning lights that provide valuable information. The list could include:

Brake system warning

Windshield washer fluid level

Coolant level

Brake fluid level

Door ajar

Headlamp door position

EGR or Check Engine

High beam indicator

Seatbelt light

Cold engine warning

Turn signals

Charging system

Transmission temperature

ABS or Anti-lock Brake System

SRS or Supplemental Restraint System

Brake lining wear indicator light. The high price of fuel created a demand for yet another light--the fuel economy warning system. When the light comes on, it tells the driver he or she is pushing too hard on the gas pedal. High manifold vacuum equals good gas mileage and vice versa. The system simply reads manifold vacuum from a sensor, and when it drops to a predetermined level, a circuit is completed and the light is lit. This has become in many models what is known as the up-shift light. An arrow on the dash indicates the time to shift into the next gear to obtain optimum fuel economy. If a warning light comes on, you must find out why. It means there is a problem either in the system being monitored or in the warning lamp circuit. Finding the actual fault is important and not very difficult. However, a wiring diagram may be needed to prevent confusion. Looking at the typical warning light circuit, you'll see that the bulb is most often supplied with current through the ignition switch. Further examination reveals the most common way of completing the circuit and getting the bulb to light is by means of a sensor, which completes the ground connection. In this case, sensor is a fancy word for a switch that turns on or off according to specific conditions. Consider a typical oil pressure warning light system. Current from the ignition switch flows through the warning lamp and from there to ground through the oil pressure switch. This particular switch is normally closed and the circuit is complete until the switch opens in response to oil pressure in the engine. Just the opposite is true with the coolant temperature sensor. It is normally open and only completes the circuit when an internal element expands (in response to heat) to close the contacts. If the vehicle has a cold engine warning lamp, the sensor includes two sets of contacts. One set is normally closed and opens as the internal element expands. This action breaks the ground circuit to the warning lamp. The other set of contacts functions if the temperature rises far enough to close them, turning on the high temperature warning. If either of the temperature lights is lit while the engine seems normal, just unplugging the wires from the sensor will provide valuable diagnostic information. If the lights remain lit, there's a short to ground in the wiring from the lamp to the sensor. The service needed isn't to the cooling system, but to the warning system. If the lights go out with the wires unplugged and the engine seems normal, it's entirely possible that the sensor has failed and needs to be replaced. Nevertheless, don't just unplug the wires and forget about them. This could be disastrous for the vehicle owner should a cooling problem develop without warning. Fig. 1: Typical coolant temperature sending unit location
Fig. 2: Oil pressure sending units may be located in a variety of places on the engine

If the starter doesn't turn over the battery is dead or you need to replace the starter.

The gas gage not working is caused by the fuel level sender located in the fuel tank this will also need to be replaced.

change fuel gauge sensor in the fuel tank

Either fuel sensor is bad or coated with sulfur residue from inferior gas. Try a can of Sea Foam gas treatment OR can of Techuron concentrate. Both available at auto parts and , of course, Walmart ! Add to full gas tank, drive 75 - 100 miles and see if all is well. If not, condide4 sensor change