My gas reads full all the time

Could be wire to sender shorted, bad sender or bad gauge. Remove wire from sender and see what happens.

you have a float arm in the tank that rises when you add fuel I think its called the sending unit in the tank with fuel pump. it could be getting defective or it could be you fuel hand gauge going defective.but biggest part of time its the sending unit in the tank, hope this helps

Fuel gauge may be the problem, but may also be a short in wires going to fuel gauge
Battery power goes to gauge in dash then to resistor in tank to ground. If the wire going to tank is shorted to frame it will always read full. Test this by disconnecting the wire going to the tank. If it goes to empty then you know the reason, either resistor in tank is bad or wire shorted.
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more than likely the sending unit in the gas tank, Could be very costly/hard to replace as you must remove the gas tank to get at the sending unit.
Very good set of instructions here: http://www.ehow.com/how_6483038_replace-gas-tank-sending-unit.html

Take a OHM meter and test the wire to the tank sender. If you have a full tank of gas you should get a reading of 8 ohms. If a hlf it will be 4 ohms. If no reading is shown you have an empty tank. Now if the meter stays at the OL setting at all times although if you bounce the Jeep to make the gas swish around and do get a reading and when the gas settles back down leveling out and returns to the OL setting the sender is bad and needs to be replaced

very common. The sender in the gas tank is the problem.
It will need to be replaced some day
Both my gas tanks do the same thing in my F250. 1 tank stays full all the time and the other drops from full to about a half tank when I get to half a tank and then works so so till empty.

Do the doors unlock when you shut the key off? Also unhook the purple wire to the sending unit in the tank, Gauge should read empty. Ground the purple wire, it should read past full. If it works this way, replace the sending unit in the tank.

I have the same problem with the 2004 V Van. My mechanic says it could be the sensor or the float. Bad news, the sensor is inside the tank on top of the float.so you drain it either way and he said the price would be about the same for either. (About $400)

I was having same issue. The cluster was the part which had to be replaced to repair it. Did they replace the cluster on your? It has to be the entire cluster I was told.

But it works ok otherwise? Be happy, it's working then. No offense, but alot of vechiles when you fill it up full, and I mean FULL will read over full, and will stay there untill tank isn't overfilled. Since your drivnig a good fuel economy car, it will take several days.