2007 Ford Ranger fuel gauge reads backwards after pump replacement (sender curve issue?)

[jcwhidby]

I’ve got a 2007 Ford Ranger (fleet vehicle) and ran into a strange fuel gauge issue after replacing the fuel pump module.

After installing a new pump/sender assembly, the fuel gauge now reads completely backwards:

• Full tank shows EMPTY
• Empty tank shows FULL

Here’s the key detail that’s throwing me off:

The original sender I removed measured high resistance at empty and low resistance at full (opposite of what I expected for a 2007). The new pump appears to be the more typical Ford curve (low resistance at empty, high at full), which explains why the gauge is now reversed.

So it seems like:

• Truck expects: high resistance = empty
• New sender provides: high resistance = full

A few questions for anyone familiar with these:

1. Did some 2006–2007 Rangers (especially fleet units) use the older Ford sender curve (~160Ω empty / ~15Ω full)?
2. Is there a known correct Motorcraft or aftermarket part number that matches this “reversed” curve?
3. Has anyone successfully swapped just the sender onto a newer pump module on these trucks?
4. Any known differences by engine (this is a 4.0L) or fuel tank configuration that would explain this?
5. Just to confirm—there’s no PCM or cluster programming option to invert the gauge, correct?

I’ve confirmed with a multimeter that the new sender is opposite of the original.

Trying to avoid dropping the tank a second time—any insight from someone who’s run into this would be greatly appreciated.

Thanks.

 

[RobbieD]

Could the float arm have been installed reversed?

Replacement parts quality is really bad these days.

 

[jcwhidby]

Good question. The float arm would only go one way. I pulled the pump back out of the tank and tried to see if it could be swapped.