Ok since I am having issues with my Fuel Level sensors I decided I needed to see what they were and how they were put together.
Ford claims that buildup of Sulfur on the contacts is causing the FLI errors and the erratic gauge issues.
So to do my own investigation I jumped in to see what I could see.
Here we go:
First remove the rear seat lower half and set it aside.
And remove the plastic cover over the tank sensor.
Just pulls off.
Here is what you see:
Next step is to unplug the electrical connector and remove the lock ring from the sender unit. Just use a drift and tap the lockring CCW to unlock it and remove it.
The Sender assembly is spring loaded and may pop up slightly when the ring comes off. If not just wiggle it a little to free it from the o-ring seal between the sender and the tank. There is a fuel line (Crossover tube) connected to the assembly. This will need to removed before you can pull the sender out of the tank. To remove it push in on the green tab while pulling on the fuel tube connector. Push Hard to get it to release. Here is a picture with the tube released and sender assy out of the tank so you can see it better.
After the tube is disconnected just carefully maneuver the sender out of the tank. Be careful of the Float attached to it.
So here is the assembly out of the car.
The Sensor is the white plastic item on the assembly.
To remove the sender simply remove the small screw at the bottom and gently slide the assembly up off the sender assembly. You will see how it comes off no problem.
This is what you will get:
Next on to what make this tick.
We need to spread some plastic ears slightly to get the cover/coil to separate from the mount plate it is on. Be careful because they can break very easily.
The Float and cover come off and we can see how this thing works:
(Sorry the picture isnt so great)
The float is connected to a plastic part that holds a contact against the variable potentiometer (Coil). As the Float rises and falls it varies the resistance on the coil.
You can remove the float to disassemble the contact from the assembly. It is held together by ears like the body. Just tap the protruding shaft to unsnap it from the ears. Careful again as they can break really easy.
Here is the disassembled unit:
Here is a poor picture of the moving contact:
I took a pencil eraser and cleaned off the coils and the sprayed it down good with MAF cleaner.
The coil seemed to have a lot of wear on it where the contact was riding on the coil. So I also slightly bent the contact so it touched on a different path.
Reassembly is just reverse of removal.
I put all back together and put it back in the tank.
Seems to be working so far. Time will tell for sure.
The Drivers side is the same setup but of course has all the pump components too.
I didn't remove it as my problem seems to be on the Full side of the tank level.
Pretty simple setup but not really reliable as history has shown so far.
Hopefully Ford improved the design and made it more robust.
But now we know how it works and what it looks like in there.
IMO the Sulfur claim could be bogus. I think it is wear that is causing the problems.
Good luck with yours and hope this helps someone out a bit.