Hello everyone,

Has anybody had the problem were there fuel light periodically comes on through out the ride when you tank is not empty? My bike just when through its 5000 mile service and it started happening.

Thanks for all your help ahead of time.

 

I haven't had that problem, but the other day my dad had to run on reserve the other day and the light never came on and the gauge was a tad over empty...
his is an 05 RK. I've read about here, that the stock H-D gauges are no good and give miss readings

 

Have you changed the gauge to one of the LED types?
If so I believe the instructions should have told you to disconnect the low fuel light because it will give false/strange readings.
I know I forgot to do that on mine and it comes on right after I fill the tank and stays on for 30 or so miles.
If you didn't install one, I wouldn't be too concerned with it, they are as Nautilus said notoriously inaccurate.
Just do like everyone else does and use one of the trip meters as a fuel gauge. Refill every 100 to 150 miles and you'll never have a problem.

 

I do have the LED light as gauge, the instructions said nothing about unhooking and wires. Can you elaborate?

 

No problem, the gas gauge works on a simple float actuated potentiometer that varies the voltage going to the gauge and the low fuel light.
The LED gauge operate with its own low fuel level setup internally.
As the fuel level goes down so does the voltage put out by the float system.
Once it goes down far enough it turns the last LED red to indicate a low level.
The problem is that if you install one without disconnecting the low level light in the speedo you now have two light setups feeding off the same voltage signal.
Separately they are fine, but added together they load the circuit (and the triggering voltage) down to the point where low light either turns on sooner than really required (like mine) or in some cases (like yours) randomly.
Remember the maximum voltage allowable in the system can't exceed about 13V because that's all the battery has to give.
So they have to use a graduated scale (of voltage) to operate the fuel gauge system.
Any extra loading will lower the voltage to the gauge and cause it to read lower than it should as well as trigger the low level prematurely.
The circuit was designed as a low voltage. low current setup so it doesn't take a lot to mess it up.

If you want to try pulling the low level line, its pin #9 on the speedo's main connector and should have a Yellow/White wire going into it.
You can either remove the pin from the connector or cut the wire.
In either case make sure you do a good job insulating any exposed wire or the pin itself.
You can get away with just wrapping the end or ends in electrical tape just to test it. But for a more permanent solution, 'borrow' a bottle of clear nail polish from the GF or Mrs. and paint the cut wire ends before putting some shrink tubing over it.
The tubing with insulate it from everything under there and the nail polish will ensure the ends are protected from any water that might get in to corrode the wire and screw things up later on.

Good Luck and let us know how you make out.

 

Don't just jump in a cut that line. I just did it on mine and the silly light is still on!!!!

Gonna have to go back to the drawing board and figure out just what the hell went wrong.
I'm hoping its just because I disconnected the speedo and because I needed to reset the clock, it may also need some running time to reset itself.
Trouble is that I won't have a chance to ride it before tomorrow night at the earliest.
There's a thunderstorm outside now and there's no chance of my riding in that.
So its going to have to wait till I get home after work.

I'll let you know what happens after I take it out and refill the tank.

 

Well I cut the Yellow/White wire to pin 9 of the speedo and instead of turning the low fuel light off, it turned it on, permanently.
OK, call me stupid.
Fortunately I’m a bit of a pack rat and try to save damn near everything I get for the bike, and my truck.
Bad thing is I’m not real good at organizing what I save.
So it took me a day to figure out where I stashed the old gas gauge and the instructions then read them COMPLETELY.

Anyway here’s what I figured out so far. When you installed the LED gauge did it have a long gray wire that wasn’t hooked up anywhere? It’s not used on all model/year bikes.


Seeing as you just had a 5000 mile checkup I'm going to guess your bike is newer than 04 and for 04 and up bikes your supposed to remove pin 9 from the speedo connector. Then you are supposed to replace it with the pin on the gray wire that comes from the new LED gauge.


Guess I'll be pulling my dash apart again tomorrow night to put the gray wire where its supposed to be.


I'll let you know how it goes. But I think my 'error' was in thinking the gauge was a simple low voltage setup, I forgot the damn speedo is full of digital electronics. Looking through the schematics it looks like as long as the voltage from pin 9 stays above a certain level it keeps a reverse bias to the transistor that powers the light. By cutting the line I just chopped off that power and turned the stupid light on.
Once I get the gray wire un zip tied from under the tank I'll try to see how much voltage is on it before I plug it in. My suspicion is that I'll be able to measure something in the range of 6 to 12V there. If that does turn the light off we'll know that all it takes is to hook it up to any switched power source on the bike to shut it off.

 

is the led gauge any better ? just bought a 04 Heritage for the wife and first thing out day 2 we run out of gas and yes gauge on full , the gauge is one of the things that I liked about the bike [ and 4000 mileson it ]

 

The LED gauge is no better or worse than the original, just nicer looking, to some of us.
Most of the 'problems' with accuracy come from the float sending unit inside the tank. They are notoriously inaccurate, so the gauges are just as inaccurate.

If your smart, you'll do what everyone else does and use one of the trip meters in the speedo to keep track of mileage. Just reset it when you fill the tank and once you have gone 100 miles stop for more.
I say go only 100 not because that's all you'll get out of the tank, but because everyone's mileage varies, a good deal in some cases, and using 100 miles as a base makes it much easier to figure how much farther you can go..
Anyway refill it at 100 miles several times, or until you get a really good idea how much gas it uses for that distance.
Once you do you'll have a better idea exactly how far you can get before you really need to find a gas station..

For the rest of you guys who are following the LED gauge low fuel light issue. I haven't had a chance to put the gray wire from the gauge to pin 9 of the speedo yet. But I did put a meter on it and it is putting out 3V and that is consistent with my idea that it would reverse bias the low fuel light LED and turn it off.
Once I get it hooked up I will attempt to run the tank down (if the weather and my work schedule will cooperate) until the red LED (low fuel) light on the gauge comes on and see if the gray wire output changes. I'm curious to see if it does and you end up with both indicators coming on or just the one on the gauge.

 

I work on equipment for a living and by logic thinking if the float hangs up and not working the gauge properly the low fuel light should work off the same float , I would think