Low Fuel Switch 1989 Gl1500

[joseph*blue]

I have got a question about the low fuel switch in the fuel tank. The light comes on on the dash when I turn the key on and then it goes off. Is this a sign the switch in the tank is working properly or do I need to check the switch another way? Thanks in advance.

[Bluewaterhooker0]

That's a bulb check. You need to verify the thermistor operation separately. The only way would be to run down to less than a gallon of fuel, or pull the fuel pump assembly out to expose the thermistor. Running tha gas down would probably be easiest, as a new gasket would be needed to reinstall the pump. Just carry a gallon gas jug with you while testing, in case the sensor is bad and you run out of gas. I don't think failed sensors are all that common, actually.

[MikeB]

It shows that the light in the dash is working.

To verify the low fuel sensor is working, you need to have low fuel.

[RockportDave]

Run it low and siphon off the rest till it comes on, then you should have about 1 gallon left.
Dave

[curtm]

Funny i just fixed my low fuel sensor issue, I the low fuel light comes on when turning the key on it usually indicates, sensor unit in tank is defective, i have read in a few posts about using a float style or a sensor out of a 56 Volkswagen , what worked for me is a simple thermister , i have an electronics background and thru some research it is not that hard if you can solder a little bit. Thermisters can be bought tru digi-key, Moeller or any electronics place for about $.50 each
Description of a thermister
therm·is·tor
ˈTHərˌmistər/
noun
noun: thermistor; plural noun: thermistors

an electrical resistor whose resistance is greatly reduced by heating, used for measurement and control. as in lack of cooling or fuel to cool it heats and allows lower resistance thus letting light illuminate,
This is the simple description, All we care about is the light turns on when fuel is low.

Some pics to show what i did

1/ Remove sending unit , remove existing thermister, (What Honda used originally), as per pics
Few things to think about , Keep tin can original thermister is encased in (Just allows new thermister not to get splashed by gas giving a false reading while driving down the road,
2/ As you see in the pic, use a piece of shrink tube in the can to not let the thermister touch metal(if it touches it will blow up as you drive) (Just kidding), but if it touches the metal can it will render the thermister to not do it's job.

3/ Thermister can be soldered it by the leads, Does not matter which way or which end, they are not polarized

pretty simple to do have a look at the pics, pretty self explanatory

,
But any questions PM me,I can do a more detailed story if needed

[Bluewaterhooker0]

""Funny i just fixed my low fuel sensor issue, I the low fuel light comes on when turning the key on it usually indicates, sensor unit in tank is defective, i have read in a few posts about using a float style or a sensor out of a 56 Volkswagen , what worked for me is a simple thermister , i have an electronics background and thru some research it is not that hard if you can solder a little bit. Thermisters can be bought tru digi-key, Moeller or any electronics place for about $.50 each""

From the 1989 Owners Manual......
Look at the last item on the page. It is NOT an indication of a failed sensor.

[WingAdmin]

If you are replacing the thermistor, make sure it is an NTC (negative temperature coefficient) and not a PTC (positive temperature coefficient) thermistor. Otherwise you will end up with a fuel low light that stays on until your fuel gets low, at which point it will turn off!

[curtm]

Bluewaterhooker0, you are correct, what i meant to say is , light will come on for a few seconds when key is turned then goes off, there is a procedure in the manual to verify if is the sensor has failed, I believe you ground the white wire on the top of the sending unit, if light illuminates , but does not work when not immersed in fuel or low fuel. the sensor (thermister needs replaced )it takes longer to get the seat off with back rest than replacing the thermister

Bluewaterhooker0 - i thing i noticed is the when i replaced the thermister, when it gets low on fuel it takes 10-15 seconds for the light to illuminate, Warming time, was going to try a 500 ohm instead of the 1K to see if it would react faster, But hey , i can wait 15 seconds

Curt

was also just thinking, might not even need to keep the can from the original thermister, (my thought was in keeping the can was to prevent splash and having the light flicker off/on etc, but with the 10-15 second delay as mentioned maybe that would not happen, it would act like a debounce timer
HMMM

We all sound pretty smart on here, Dont we

[joseph*blue]

Thanks everyone for the help on the low fuel light and switch on my 89' Goldwing.