low fuel lite

[skene]

Ran out of gas and discovered lite not working on 2002 Monster S4. Checked system and discovered sending unit not working. Bought a good used one on ebay but it doesn't work on the bike. Can't beleive they are not all the same.
Any ideas?

[Howie]

Disconnect the sensor.  Jump the wires for the sensor.  Turn the key on.  If the bulb lights, then the bulb and wiring are good.  If the bulb does not light, either the bulb or wiring is the problem.  Since your bike is fuel injected, there are four wires, two for the pump and two for the sender, not two like the carbies.  The S4 on line owner's manual is missing the wiring diagram, so you will either have to find a wiring diagram or wai for someone else

[skene]

wiring diagram in the owners manual.
Wiring and bulb good, sender on the bench. Sealed unit! Cost $175.00 new. There are different part no. but thought the unit is triggered by the float. Spare works but not on bike?

[ducpainter]

Are you checking continuity on the bench?

Maybe the float has a leak and fills with fuel.

[skene]

continuity checked on the bench.
No leak in float.
Not sure if float has metal contact.
Looks like I will just have to buy the correct part.

[ScottRNelson]

Any ideas?

Use the trip odometer.

On all three of my bikes I refill between 100 and 120 miles.  If I'm on a longer ride with all highway riding and no stop and go, I'll go to 150 on all but the 888, but I've found trip odometers to be way more reliable than a low fuel light.