fuel gauge

[roadkingdresser]

 Hi, friends got a 2011 softail blackline fxs -the fuel light is flashing in the speedo and it says low reserve or dist. thought it was low on gas but only took 1 1/2 gallon to fill. Anybody have this problem or can give me some input to look for. Thanks

[bump]

I had the fuel gauge on my 02 FLHTC do that and some other weird stuff. Replaced gauge in fairing and cured that problem.

[smoserx1]

That sounds like a sending unit issue to me.  Does his bike have a gauge as well as the light?

[roadkingdresser]

no just has the light, we worked on it today and cleared the code a couple times. keeps saying low fuel and something about low circuit.

[smoserx1]

Parts diagram shows a sending unit 75276-08A.  Don't know what else it would likely be if no gauge.  I know I have had to put a sending unit in my FLHT 4 or 5 times now and every time they fail it reads all over the place (I have a gauge but no light).  The part for his bike is not very expensive (mine is about 2X as much).  If you can't fix it by clearing codes or resetting things that would be my next step.

[Rusticwater]

That sounds like a sending unit issue to me.  Does his bike have a gauge as well as the light?

no just has the light, we worked on it today and cleared the code a couple times. keeps saying low fuel and something about low circuit.

Whenever this topic comes up there's a lot more to the fuel gauge circuit than meets the eye. And checking the wiring diagram it indeed appears the 2011 FXS doesn't come with a fuel gauge. To replace the necessary voltage divider circuitry the fuel gauge normally provides, Harley instead used a "resistor assembly." Is this plugged in? The wiring diagram can be found in the library here.

Usually when you remove the fuel gauge, for the low fuel light and distance to empty readout to still work properly you need to add some resistors in. Performance Machine sells a unit for example, this Harley "resistor assembly" probably serves the same purpose.

[roadkingdresser]

couldn't seem to find the thread any chance you could lead me in the rite direction? thanks

[Rusticwater]

The original thread from 2014 is here. There's a lot of discussion how the fuel gauge, sender, and signal to the speedometer for low fuel and distance to empty is based upon a voltage divider circuit. When I read your post about the low fuel light not working, etc., this post came to mind.

Next, here's a screenshot of the wiring diagram for the 2011 FXS. See the fuel sender unit on the left side? Note how a yellow wire comes out of the sender and branches, one branch goes up to the speedometer and the other branch goes over to a "resistor assembly." Now a regular Harley that has a real fuel gauge wouldn't have that resistor assembly, the fuel gauge would be there instead. Since the FXS doesn't have a fuel gauge the Harley engineers substituted that resistor assembly, which I believe is part number 72677-11.
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Here's a closeup of the resistor assembly:

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So where is this resistor assembly plugged in? If you look at item 92 in the diagram here it appears it might be by the ECM plug, maybe under the seat?

[smoserx1]

That is a good pic of the wiring diagram.  I found the diagram yesterday in the library.  Like FSG said in a recent unrelated post some of us have to edit these URLs from www.box.net to app.box.com to make 'em work.  Anyhow since the diagram shows the 3 colored wires from the main harness to the resistor assy it should be easy to find.  Ronnie's site shows the resistor assy as pn 72677-11 for $9.49, so it sure won't break the bank if you want to try replacing that first.  My bet is still on the sending unit though simply because I have had so many of them go bad.

[roadkingdresser]

THANKS GUYS,goin to look into the resistor and if that doesn't help,it's goin to be the fuel gauge next. thanks again for the help