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There have been a few questions on how to solve this problem.
I got into it today a little more, and here are some tips.
First, the NO FUEL light circuits are not electrically connected or in common with the fuel gauge. They even have separate sending units..
NO FUEL as well as AUX FUEL PUMP are controlled by the liquid level sensor which is located in the left top of the fuel tank. Note that the fuel gauge sensor is in the right rear top of the tank.
The liquid level sensor has two floats on one unit; each float controls either NO FUEL or AUX PUMP. Each float controls a switch internal to the sensor, and the switch is either open or closed. In the case that the tank is halfway filled the switch for the AUX PUMP is closed; it opens and shuts off the pump when the float determines that the tank is full.
Same condition as above but the NO FUEL switch is normally open; it will close when the tank is empty.
So, if one has a NO FUEL error light when there is actually fuel in the tank, an easy way to test the sensor without removing it is to (unfortunately) remove the rear panel. Disconnect the connector coming out of the sensor -- it'll be two red wires and two black wires running through a white connector.
It will be a four pin connector. The top of the connector has a point on it-- sorta like a roof, and the bottom of the connector is flat. That makes the connector "murphy proof". The top two pins (near the angled edge) are 1 and 2 and are the output of the AUX PUMP switch. The bottom two are 3 and 4 (naturally) and are the switch output for NO FUEL. This can be tested with a continuity tester. 1 and 2 should be normally closed and 3 and 4 should be normally open if the tank is, say half full.
If you don't have a continuity tester -- no problem. Simply disconnect that connector and crank the engine. By disconnecting the connector you simulate an open switch which indicates fuel in the tank. If it cranks over then the liquid level sensor is bad.
Now, just because it is bad doesn't mean it can't be fixed. You'd have to remove the sensor and chances are you will find some sort of corruption or corrosion that is not letting the float move freely.
Note that the switches are inside the aluminum tube on which the floats are mounted, so you can't see the switches when looking at the sensor.
Note that while the liquid level sensor works identically in the 802a and 803a, the sensor itself is not the same for both units.
Hope this helps ----
zarathustra
I got into it today a little more, and here are some tips.
First, the NO FUEL light circuits are not electrically connected or in common with the fuel gauge. They even have separate sending units..
NO FUEL as well as AUX FUEL PUMP are controlled by the liquid level sensor which is located in the left top of the fuel tank. Note that the fuel gauge sensor is in the right rear top of the tank.
The liquid level sensor has two floats on one unit; each float controls either NO FUEL or AUX PUMP. Each float controls a switch internal to the sensor, and the switch is either open or closed. In the case that the tank is halfway filled the switch for the AUX PUMP is closed; it opens and shuts off the pump when the float determines that the tank is full.
Same condition as above but the NO FUEL switch is normally open; it will close when the tank is empty.
So, if one has a NO FUEL error light when there is actually fuel in the tank, an easy way to test the sensor without removing it is to (unfortunately) remove the rear panel. Disconnect the connector coming out of the sensor -- it'll be two red wires and two black wires running through a white connector.
It will be a four pin connector. The top of the connector has a point on it-- sorta like a roof, and the bottom of the connector is flat. That makes the connector "murphy proof". The top two pins (near the angled edge) are 1 and 2 and are the output of the AUX PUMP switch. The bottom two are 3 and 4 (naturally) and are the switch output for NO FUEL. This can be tested with a continuity tester. 1 and 2 should be normally closed and 3 and 4 should be normally open if the tank is, say half full.
If you don't have a continuity tester -- no problem. Simply disconnect that connector and crank the engine. By disconnecting the connector you simulate an open switch which indicates fuel in the tank. If it cranks over then the liquid level sensor is bad.
Now, just because it is bad doesn't mean it can't be fixed. You'd have to remove the sensor and chances are you will find some sort of corruption or corrosion that is not letting the float move freely.
Note that the switches are inside the aluminum tube on which the floats are mounted, so you can't see the switches when looking at the sensor.
Note that while the liquid level sensor works identically in the 802a and 803a, the sensor itself is not the same for both units.
Hope this helps ----
zarathustra
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