Possible cause of wrong fuel level but good sender and gauge.

[Lil-Pony]

Yesterday i was pulling apart my 84 broncos interior and i found a little box in the center console labeled low fuel level something or other, i have the information center in my middle console as well, i got me thinking doe this just sample the fuel level wire or does it modify the resistance in the wire... Even if it samples it could be causing a short from the wire to ground or positive voltage... Any one know about this

 

[RonD]

On the '84 you would have the 73(Empty)-10(Full) Ohms sender and gauge, '89 and up use reverse of that(16-158 Ohms), just FYI.

I would think that "box" would be for a low fuel level light, it should not change anything but would be connected to sending unit/gauge wire, so could if it was broken.
As the ohms increased, getting closer to 73ohms, the low level light would start to flicker, or if it is connected to the dash(which is likely, because it was an option), then it would come on steadily when ohms reached the trigger point(65ohms, maybe).

 

[Lil-Pony]

I under stand all that what im saying is that this sensor could it be acting like a partial second ground bring the final restance closer to 10 ohms which is what mine is doing, barely moves off of full... Sender is new tried a second gauge same results