low fuel light always on (1 Viewer)

[Kernal]

While the pump bracket is out check for chafing of the green ground wire that crosses the bracket, it's been known (rarely) to chafe all the way through the insulation against the bracket.

This doesn't show the chafed wire insulation but if you look closely you can see where the wire had been rubbing against the bracket. Some people have either zipped tied the green wire to the bracket or put a small rubber hose around the wire at that location, or used a section of heat shrink tubing over the wire at that point:

 

[wma86]

Just unplugging harness at the tank will net info, if the light goes out, the problem is in the tank, if not it's harness or cluster.

I did this and you were correct. Pictured are when plugged in and then when not plugged in.

Thermistor on the sending unit is bad or wire is shorted.

what’s the best process to diagnose that?

 

[veiloctane]

I did the same thing change my cluster with LEDs and low fuel light is on. Anyone have a FIX?

I just put back the factory bulb no more issue.

 

[irwinsg]

I just put back the factory bulb no more issue.

Awesome. Will roll everything back. Dammit

 

[veiloctane]

Awesome. Will roll everything back. Dammit

yeah took me a while to figure it out but alot of 4runner guys have this issue after swapping to all LEDs... i asssume that theres always a little current flowing as the lower the fuel gets the brighter the light gets.

Toyota-4Runner.org

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[veiloctane]

Awesome. Will roll everything back. Dammit

no need to revert all led bulbs just the one for the low-fuel light

 

[irwinsg]

no need to revert all led bulbs just the one for the low-fuel light

Did that first, no change. If yours are all still LED, then I guess I have a different problem...

 

[wma86]

Hey folks, I am still stuck yet again with mine illuminated all the time. I have diagnosed to connector and when doing that, the light goes out. I just swapped out my sending unit with another one and the darn low fuel light is still on.
The fuel filler neck from where the pump goes in to the tank is brand new.
I also checked the green wire on both for chafing and it was in near perfect condition. @Tools R Us
Lastly, the fuel pump was tested with a meter and checks out as well as functioning. I am literally baffled……
@fjbj40

 

[irwinsg]

Hey folks, I am still stuck yet again with mine illuminated all the time. I have diagnosed to connector and when doing that, the light goes out. I just swapped out my sending unit with another one and the darn low fuel light is still on.
The fuel filler neck from where the pump goes in to the tank is brand new.
I also checked the green wire on both for chafing and it was in near perfect condition. @Tools R Us
Lastly, the fuel pump was tested with a meter and checks out as well as functioning. I am literally baffled……
@fjbj40

If it helps...
Mine was perfect into I swapped out the dash lights. I'm skeptical about it being the sending unit, but there's no doubt it makes sense.

What bugging me is a few of the LEDs that I swapped in aren't working, and I assumed I didn't seat them correctly. But if that's not it, then the LEDs are screwing up the system somehow, and that bulb is getting too much juice because of it.

That light slowly lights up at the fuel goes down, so it's calibrated to some extent. It might not take much to screw it up, and we may be locked in to the incandescents. One I can't stand it any longer, I'll roll back to oem for every single bulb unless someone had a solution before then

 

[veiloctane]

With these old trucks the membrane is easy to tear.

With some leds not working could be a broken circuit or even a led in reverse check polarity.

Incandescent light only for the low fuel light. That’s what fixed it for me.

Check continuity on the membrane circuit.

 

[wma86]

With these old trucks the membrane is easy to tear.

With some leds not working could be a broken circuit or even a led in reverse check polarity.

Incandescent light only for the low fuel light. That’s what fixed it for me.

Check continuity on the membrane circuit.

Thanks. I don’t have LEDs in mine, all OEM. I plan to take the dash out to replace the driver light which is out so can check at that point.