I would guess the level sensor float-arm is stuck - try banging the bottom of the tank with a 2x4 piece of wood - not too hard, just seeing if the arm will come loose.
If not, essentially the only way of getting at the sensor is by dropping the gas tank.
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why would a speedometer stop working on a Mazda
Because they are broken is one reason
Blown fuse.
Electrical connection issue.
It could be the fuse, but mine is because the floater that measures for the gauge is stuck.
temperature gauge not working can be caused by a bad temp sensor in engine, a bad gauge in dash, or a bad fuse
The problem would be that the car is messed up
There are several reasons why a gas gauge could stop working. A short in the wire from the sending unit could be the culprit. The computer that controls the dashboard gauges could be going out.
Either the throtle cable is hanging or the idle control solonoid is not working
Check the fuses first!
Probably a ground wire issue.
A common cause for a gas gauge to stop working in a 1994 Ford Aspire is a defective fuel gauge. Lose wiring in the dash is another cause.