My fuel gauge quit working and the low fuel light as well as the low range message shows on the digital display. A small red indicator light is also lit up.
I'm guessing the fuel sending unit is bad? Does anyone know how to test the sending unit and the fuel gauge ? Bike has approximately 12000 miles on it, seems a little early for this to fail.

 

small red indicator is telling you there is a code stored. Pull that and we can work from there.

 

Also check your fusebox.

 

As stated the red key means a code is stored. There is a combination of things to press to get the code to display. Once you have that it should point you in the right direction.

 

To the best of my knowledge, there is NO way to test either component!
No diagnostic to find which one is failing, I have asked a few mechanics and have been patiently waiting on this forum for years to find an answer to that very question and ,,, nothing.

Pretty much everybody with Harley's notoriously failing fuel gauge uses the trip odometer to determine "real time" fuel in the tank.
Figure out your mileage and watch the trip odo,

 

Thanks, I haven't checked codes yet or the fuses but I did find some mangled wiring today above the rear tire. I lowered the bike 1.75" a couple weeks ago and tried it out with me and my wife...no problem ,then I took my daughter for a ride earlier this week and you know the rest of the story. Not sure if the fuel gauge issue is related but probably so. Thanks for the response. I'm used to watching my milea
ge but the little blinking light is irritating.

Thanks for the suggestions, now I know where to start

 

2012 has a BCM that handles the chore the fuse box used to do (over simplified explanation). There are only two of three fuses on a 2012 FXDC.
To check codes hold down trip button on left control while turning key to on. Trip button then to scroll through codes

 

Thanks again to everyone who offered advice. I replaced the mangled wires and amazingly everything is working again. I adjusted my shocks to the highest setting and will try it out when the weather permits. The bike fits me better lowered but K Say Raw , you don't always get what you want.