Fuel gauge works, Low fuel light always on, Except for first few seconds at start up. Is this sending unit in tank or does it work off pressure? Is this an esay fix?

 

It's the sending unit.

You want to do it and write an essay?

 

I'm working on a problem with my fuel guage and light right now as well. My truck has had an issue with the guage not being very accurate since I've had the truck (about 10 years). The guage would act esspecially unstable when the tank was full, but the low fuel light worked well. I had the bed off while working on a paint job a couple weeks ago and decided to replace the sending unit since the top of the tank was exposed. Their is a large plastic nut (approx 5-6") on the top of the tank that holds the fuel pump/sending unit/etc in the tank. I removed the eletrical connector and two fuel lines and the whole thing lifted out. The sending unit is basically two arc shaped potentiometers that have the wipers moved by a float. Three wires connect to it with spade connections. I swaped the sending units, put the assy. back in the tank, reconnected the supply fuel line with a new plastic clip since the original cracked (they are Ford clips available in Help section of Autozone or similair), put a small hose clamp on the return line to replace the one I had cut off, and reconnected the wires. The truck was undergoing lots of work at the time and I didn't actually drive it and put fuel in until a couple of days later... well the guage now stays on empty or slightly above, and the low fuel light stays on as well. I haven't investigated this yet, but I will soon. I'll post the details here.

 

That sounds like you may not have gotten a good ground back onto the new sender - or possibly not a good connection on the low-voltage feed from the gauge...either way I'd double-check the spade connections(where they crimp onto wire maybe?) and/or grounds first. Good luck! :-)