How do you get the fuel gauge to reset if the gauge shows full and the low fuel light stays on?

Answer 1

I'm not sure what type of vehicle we're talking about here, so this could be multiple issues depending upon the circuitry & therefore what commands that light on. I can tell you this, I'm a pretty well versed mechanic and I can't recall seeing a "reset" button for a low fuel indicator. Most of them feed directly off of the fuel sending unit in one fashion or another (the same thing in the tank that tells your gauge where to be.) That being said, it's reasonable to assume (assumptions are always just that, assumptions) that if the gauge is good and the light is on, there is an electrical issue of some sort. Generally speaking all of the lights in the instrument power are constantly provided power (Battery +) from a common source when the ignition is turned to the "RUN" or "ACCESSORY" positions. The lamps are then illuminated by means of providing ground in some way depending on the specific system & design. So, it's quite possible that you have a short somewhere providing said ground, and thus illuminating the lamp. There are also some systems where the one of the onboard computers controls the lamp...NO, I'm not saying the computer is bad, it's not likely at all. What I am saying is that there is a possibility that somewhere, by whatever means the computer uses to interpret when to light the lamp, there is a problem. You might want to have that looked at. In the unlikely event (I say this because the gauge still works) that the fuel sender has a short in it you'd want that taken care of considering that the fuel sender sits submerged in fuel and shorts tend to produce heat. Don't worry too very much though, if the short was that bad it SHOULD blow a fuse and the heat generated by the fuel pump (that's also submerged in and cooled by fuel) is fairly substantial anyway. I've always wanted to know what "genius" tried that one out first. I mean I know that the odds of an in-tank fuel pump causing combustion are extremely, extremely low. This is due to the fact that the motor is SUPPOSED to be covered fuel at all times (by design, even when the tank is empty, again by design)...and that this is supposed to seal any of the necessary oxygen for combustion away from the electrical arcing (read that: sparks), and that it's the vapors that combust not the liquid, and that as long as the fuel tank is sealed and the vapors properly vented the tank is starved for air. BUT I STILL BET the people who came up with the idea stood plenty far away from the tank when they first tested it (have they never heard of cavitation [think about a boat propeller in the water making all those air bubbles because it's spinning so fast], the pump turbine is running at thousands of RPM's!) I know it works and we all have proof it does (you just don't regularly see cars spontaneously combusting while driving down the highway), but it still is somewhat of a bewilderment to me.