2010 Hyundai Sonata. Fuel gauge always reads full regardless of fuel level. Have replaced tank sending unit. No difference.

If the gas gauge of your 2007 Dodge Nitro R/T always shows a full reading, there could be a few possible causes for this issue:

1. Faulty fuel level sensor: The fuel level sensor is responsible for measuring the amount of fuel in the tank and sending that information to the gauge on the dashboard. If the sensor is malfunctioning or stuck in the "full" position, it will consistently display a full reading on the gas gauge.
2. Wiring or electrical issue: There might be a problem with the wiring or electrical connections between the fuel level sensor and the gauge. If there is a loose or damaged wire, it could prevent the accurate transmission of fuel level data to the gauge.
3. Instrument cluster malfunction: The problem could be with the instrument cluster itself, where the gas gauge is located. If there is a fault in the cluster's circuitry or display, it may cause the gauge to always show a full reading.
4. Gauge calibration issue: In some cases, the gas gauge might be improperly calibrated, resulting in it always displaying a full tank. Recalibrating the gauge might resolve the issue.

To address this problem, it is recommended to take the vehicle to a qualified mechanic or an authorized Dodge service center. They will have the necessary diagnostic tools and expertise to identify the exact cause of the issue and perform the required repairs. They may need to inspect the fuel level sensor, check the wiring connections, or evaluate the instrument cluster to resolve the problem.

The fuel level sending unit inside the fuel tank is bad or the gauge is or there is a wiring problem This video is for a mercury vehicle , but all makes an models are the same . Repairing Fuel Gauge Problems 2004 Mercury Marquis EricTheCarGuy

Defective fuel level sending unit inside the fuel tank.

It sounds like the sending unit to me also and it would be worth the price of a fuel pump to not have to drop the gas tank again for a while.

Turn the ignition on and off several times before inspecting the gas tank because a blown fuse is the usual cause for fuel gauge malfunctioning. If the gauge remains motionless, check your fuse box and determine the fuse's location using your service manual.
Replace the fuse if the link is broken or damaged. Then, inspect the gauge's wire connections for cleanliness and make sure the wires are connected.
Turn the ignition switch to the "off" position. Attach one end of a jumper cable to the fuel-gauge terminal behind the gauge itself. Attach the other end to the ignition terminal.
Replace the sender unit in the gas tank if the gauge reads full and your car does not have a full tank. Replace the fuel gauge if the needle remains inoperative.

Sorry to say,but the fuel sending unit is the problem,the fuel tank will have to be lowered out of the vehicle to replace the unit.If the fuel sending unit is not available by itself you will have to replace the whole fuel pump assembley.

The sending unit in your tank is going bad replace it.

This is a normal concern.
The instrument cluster uses 4 different operating modes to calculate the fuel level:
Anti-slosh (default mode)
Key OFF fueling
Key ON fueling
Recovery
After a fuel fill up, the time for the fuel gauge to move from empty (E) to full (F) ranges from 2 seconds to 55 minutes depending on which operating mode the fuel gauge is in.
The default fuel gauge mode is called the anti-slosh mode. To prevent fuel gauge changes from fuel slosh (gauge instability due to changes in fuel sender readings caused by fuel moving around in the tank), the fuel gauge takes approximately 55 minutes to go from empty (E) to full (F).
The key OFF fueling mode (2 seconds to read empty [E] to full [F]) requires 3 conditions be met:
The key must be in the OFF position throughout the entire refueling of the vehicle.
At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
The instrument cluster must receive a valid key ON fuel sender reading within 1 second of the key being put into the RUN position. The key ON sample readings are considered valid if the fuel sender reading is between 15 ohms ± 2 ohms and 160 ohms ± 4 ohms.
If these conditions are not met, the fuel gauge stays in the anti-slosh mode, which results in a slow to read full (F) event.
The key ON fueling mode (approximately 90 seconds to read empty [E] to full [F]) requires 3 conditions be met:
The transmission is in PARK (P).
The key is in the RUN position.
At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
In key ON fueling mode, a 30-second timer activates after the transmission is put into the PARK (P) position (automatic transmissions). When the 30-second time has elapsed and at least 15% of the vehicle's fuel capacity has been added, the fuel gauge response time is 90 seconds to read from empty (E) to full (F). When the transmission is shifted out of PARK (P), the fuel gauge strategy reverts to the anti-slosh mode. The key on refueling mode prevents slow to read full events from happening if the customer refuels the vehicle with the key in the RUN position.
Recovery mode is incorporated into the instrument cluster strategy to recover from a missing fuel level input during a refueling event. Missing fuel level inputs result from intermittent opens in the fuel sender or its circuits. Recovery mode (empty [E] to full [F] approximately 20 minutes) is initiated when the following 2 conditions are met:
The instrument cluster is in the anti-slosh (default) mode.
The actual fuel level in the tank is greater than what is being displayed by the fuel gauge

this is an old post so not sure if problem has been resolved ?? but if not ? from your symptoms it sounds like the fuel tank sender unit is faulty and unfortunately not servicable but not too expensive to diy a new unit for a quick confirmation it is sender ? remove the wire from sender unit then scratch /hold to good earth whilst ignition is turned on and fuel guage is read by assistant ? if guage goes to full ? sender is faulty hope this helps?

You don;t say whether the fuel gauge is reading accurately, or whether it's always on empty. If the gauge is always showing empty, it's most likely a problem with the sending unit in the fuel tank. Check the resistance across the two terminals of the sending unit.

On a C900, the fuel sender level unit is separate from the fuel pump and located on the right side top of the tank, accessible by removing the trunk floor lift up panel (the pump is located on the left side top of the tank.
Possible problems are: electrical line off or broken, float not working (it's fairly delicate); or gauge not working.

Test the resistance of the sending unit with the lines disconnected, the resistance should be 2.6 to 3.8 ohms full tank, 63.3 to 67.5 ohms empty tank; and test for voltage across the top of the sender unit, if no voltage, that's likely the problem!

If the gauge is otherwise reading accurately (showing 'full' for a full tank, etc) then the problem is likely a gauge malfunction and can be simply replaced.

Good luck!

Saabreur