Fuel gauge failed-"low fuel" displayed

[600remguy]

Was under the dash of my 2 day old, new to me, '04 Sport Trac installing a remote starter last Sunday. This does not involve any dashboard hook ups, just under dash. When I backed out of the shop, the dash "dinged" a low fuel warning and the gauge was as low as it could go below empty. When I started, the tank just under 1/4 full. I filled the tank the next day with no change. No change the rest of the week. Yesterday I went back under to look around. I could find nothing at all that I might have done to cause this. I checked all connections that I could see, one by one and made sure they were all snug. I followed the wiring as much as I could to the tank and above it to the sending unit connection. About the only thing I haven't done is get to the instrument cluster connections.

Has anyone else come across this? The previous owner said he had no indication what-so-ever of a gauge problem. I hope this hasn't been beat to death before. I couldn't find any threads that applied. This site sold me on my Sport Trac and has already helped me figure out things like where the key-less entry code is/was.

 

[600remguy]

Solved my own problem today. Turns out it was sorta my fault, but just sorta. Thanx to ncranchero for the wiring diagram and diagnostic for dashboard problems, I started looking for a broken circuit, as well as investigating the fact that the chime didn't sound with the key in the ignition and the door open. Anyway, it turns out that the large 70+ wire chassis to dashboard plug is/was to blame(the plug in my '72 Mach dad like 6 wires). This plug sits/fits in some sort of bracket back in behind the fuse panel and mine will not seem to clip into said bracket and will move up and down if moved. This is the cause of my broken circuit. It seems to only effect the fuel gauge. Another queer thing is that said plug looks as if it has been chewed on by a raccoon or gouged with a screwdriver or something. That part is a mystery to me. Manipulating the plug into different positions made my gauge come back to life so I left well enuff alone when it was working again. I had only maybe bumped this plug while running a wire passed it for power from the parking lights. Maybe this will help someone else.