Fuel gauge

[jrchilds]

Have a 2017 Low Rider that my son dropped. Tank and rear fender were damaged and repaired. Looks Perfect. New Bars, shift lever and assorted parts on the right side of the bike replaced. Put the Harley kits on the rear fender to mount a removable sissy-bar which required the cutting of and splicing the wires to both rear turn signals. installed a woods 555 cam and inner bearings, power vision, target tune and Bassani 2-1 pipes.
Bike runs great, looks great. Only problem is I cannot for the life of me get the fuel gauge, low fuel light and LO RANG indicators to work . I listed all the things I have done to give you guys of just what has been done to the bike so that you may be able to point me in the right direction. Checked all the wiring inside the steering head at least 3 times, pulled the tank indicator out and it seems ok, resistance changes as the float is moved. I'm stumped.
Thanks,
Jack

[koko3052]

I've never had a fuel gauge read properly that was more than a month old!

[smoserx1]

On the older bikes you could test the gauge by separating the sending unit connector then jumping the 2 pins on the bike harness that the sending unit plugged into.  If the gauge and wiring were ok the gauge should read full by doing this.  What is a LO RANG indicator?

[jrchilds]

Low Rang Shows up where the mileage, trip indicator, clock and gear indicator show up below the speedometer. Will try jumping the wires.
Thanks
Jack

[Rusticwater]

Does the backlight on the fuel gauge work? Do you have a wiring diagram?

[chaos901]

Also, when turn the IGN on and all the lights on the instruments come on for a second, does the LOW FUEL light come on then.  Just want to see a positive before trying to find the fault.

[jrchilds]

Yes, the backlight on the fuel gage comes on, and then low fuel indicator lights up.
Jack

[Rusticwater]

So the fuel gauge, aside from the back light, doesn't work at all?

Are there any codes, like B1004 and B1005?

Unplug the fuel pump/sender. To test the sender, use a good Ohm meter and measure the resistance between terminals B & C. Is it greater than 350 ohms? If so, the sender is bad. If not, I'd be looking at the gauge itself, or a fault in the wiring between the two.

Both the fuel gauge and the sender work together in a voltage divider circuit (the yellow wire) to send a signal to the speedometer for the low fuel/low range indicators to activate.
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[jrchilds]

Thank you for your help, will do as you sugest tomorrow. I have a manual, but it's for 2015 and I'm not sure what has changed. And I have no understanding of can-bus . I never saw the small drawings of the sender and fuel pump, but it's just as I imagined. And I had no idea how to test the sender properly. I  just took it out and made sure the resistance changed when moving the float.

[Rusticwater]

Thank you for your help, will do as you sugest tomorrow. I have a manual, but it's for 2015 and I'm not sure what has changed. And I have no understanding of can-bus . I never saw the small drawings of the sender and fuel pump, but it's just as I imagined. And I had no idea how to test the sender properly. I  just took it out and made sure the resistance changed when moving the float.

Good luck, hopefully it's something simple. I have a 2010 Dyna, the fuel gauge and sender are the same. The procedure I posted is from the Electrical Diagnostics Manual.

[jrchilds]

Got 960 ohms resistance on the sender. One is now on order I have a shop manual for 2015 Dyna's. My second one. This one is blue, not green. Here's a pic

[hattitude]

Just make sure to check all the simple stuff first.....

I was doing some work on my '03 Heritage. In the last three months, I've taken the tank off,  four times......

The gas gauge stopped working and after doing some checks, it seemed there was a broken wire in the harness. I double checked all the connectors in the circuit and found one with a bent pin. Straightened the pin and all was well....

So... make sure to check all the connectors/connections before buying new parts or digging into the wiring...

[jrchilds]

Ok, got a new fuel pump sender, still no reading. Will check again the connections, a bent pin is always possible for a guy with 10 thumbs (like me).
Thanks, Jack

[jrchilds]

No bent pins, when the 3 wire connector under the left side of the tank is disconnected the light on the fuel gauge is out. So it is getting power. Must have had the top of the fuel tank that was just custom painted apart 10 times. Stumped
Jack

[hattitude]

No bent pins, when the 3 wire connector under the left side of the tank is disconnected the light on the fuel gauge is out. So it is getting power. Must have had the top of the fuel tank that was just custom painted apart 10 times. Stumped
Jack

Interesting..... similar to what I had...

The gauge was lit, showed empty, with the low fuel light on in the gauge.... I knew the gauge was getting power, so I disconnected it at the left side of the tank. The gauge has the male side of the AMP connector.

I forget the procedure, but there was a way, in the electrical diagnostic manual, to check the gauge and the wires in the female connector from the harness side.

The wires in the female connector didn't check out correctly, so I figured it was a broken wire in the harness behind that connector somewhere.

When I removed the tank to get access to the wire harness, I noticed a bent pin in the male connector (tank side), on top of the tank to the fuel float sending unit....  That's the one that fixed mine and saved me from getting into the wire harness, looking for a broken wire that wasn't there....

I'll try to find that gauge test again in my manual, and post it up if I can find it...

[hattitude]

No bent pins, when the 3 wire connector under the left side of the tank is disconnected the light on the fuel gauge is out. So it is getting power. Must have had the top of the fuel tank that was just custom painted apart 10 times. Stumped
Jack

Interesting..... similar to what I had...

The gauge was lit, showed empty, with the low fuel light on in the gauge.... I knew the gauge was getting power, so I disconnected it at the left side of the tank. The gauge has the male side of the AMP connector.

I forget the procedure, but there was a way, in the electrical diagnostic manual, to check the gauge and the wires in the female connector from the harness side.

The wires in the female connector didn't check out correctly, so I figured it was a broken wire in the harness behind that connector somewhere.

When I removed the tank to get access to the wire harness, I noticed a bent pin in the male connector (tank side), on top of the tank to the fuel float sending unit....  That's the one that fixed mine and saved me from getting into the wire harness, looking for a broken wire that wasn't there....

I'll try to find that gauge test again in my manual, and post it up if I can find it...

Ooops, just noticed that Rusticwaters posted all the electrical connections for your bike.... my manual is for an "03, so not going to be applicable to your 2017 bike...

Good luck with the repair...

[Rusticwater]

No bent pins, when the 3 wire connector under the left side of the tank is disconnected the light on the fuel gauge is out. So it is getting power. Must have had the top of the fuel tank that was just custom painted apart 10 times. Stumped
Jack

You don't mention what the resistance reading of the new sender is...

Just to be clear, without opening the fuel tank again, unplug the fuel pump/sender connector. On the connector attached to the tank (not the bike's wire harness), what's the resistance between pins B and C?

[jrchilds]

I am starting to think it's the gauge itself that has a open connection.
Jack

[jrchilds]

resistance between B and C is 230 ohms, about 1/4 tank.
New sender is between 470 and around 200.
Thanks,
jack

[Rusticwater]

Referring back to the wiring diagram I posted and looking at the yellow (actually W/Y) wire that runs between the speedometer, fuel pump, and fuel gauge connectors, you may want to make sure there is continuity between all three.

There was a thread posted here from years ago that went into detailed theory and operation of the fuel gauge circuit (unfortunately some of the diagrams are missing).

[jrchilds]

Fixed it, gas gauge wired incorrectly when repainted.
Jack