My gas gage on my 1996 mazda is not working but all other gages are what is wrong

I didn't see an s15 in that model year, in my database?
If the speedometer works but the tach doesn't, I think something is wrong with instrument cluster?
GM has had a problem with fuel gage sending units. The sending units are not hard wired to instrument cluster, they send signal to pcm, the pcm sends serial data to instrument cluster, telling the cluster the gage settings.
It may be possible to use different size resistors in place of the fuel level sending unit, to see if fuel gage reacts properly to different resistors, if the gage reacts properly, then I think the problem is the fuel gage sending unit.

Someone will need to check the circuit at the gas tank, the sending unit next to the pump grounds the gauge on the dash. You should have a voltage reference at the tank from the gauge.

One fuse operates all the gages, so no the fuse is not the problem, the problem is that the gas gage sending unit (a variable resistor) that senses the level of fuel in the gas tank is defective and needs to be replaced, this is the most common problem with any fuel gage problem

Are you sure the fuel gage is reading accurately most gages just use a resistor to gage how much fuel is in the tank over time its easy for the gage to read off could be running out of gas unless you know for sure it still has a half a tank?

99% of the time this is caused by a defective fuel gauge sending unit in the gas tank, in fact that is the only thing i have ever found wrong in my 40 years as a mechanic, 30 of which were at a Ford dealer.

have you tried working on one problem at a time?
have you check the body computer for any codes?
and to also verify the bus line is ok.
if you find nothing wrong with BCM or bus,
try checking the speed sensor for an output signal or if the gear is bad.

Faulty Fuel Pump, and run an injection cleaner into your gas tank (you can buy a bottle at your local parts shop) then get the fuel filters checked or replaced.

Chances are contaminated gas clogged your fuel works.

For a quick fix: Open the gas cap at 1/4 tank to relieve the vacuum. it will make your pump work less.

Is......the problem--"the gas gage reads empty when there is fuel in the tank. OR, The gage moves when the key to turned off ?

If it's the first,
You will need to test the gage and through process of elimination, determin if the Sending unit inside the fuel tank has gone Bad.

If its the second ? - Electrical gauges will move when powered down. Normal

Testing the gauge may not be easy - just depends on your ability.
It is a simple 2-wire gauge circuit, when disconnect (usually need the fuel tank) the gage reads in one direction (either full or empty)
then when shorted-the gage reads in oppisite direction.

Of course you must select the correct wires or you may short out the wrong circuits!! Most GM vehicles use a purple wire & black wire.

A quick method I have used to check the in-take part of the gauge is this.
1st. know there is gas - 1/2 tank works best.
2nd driver's door open, key in run position, engine not running.
3rd gently lift up on the door then let if come back down, gently.
just enough to cause the gas to slosh around.
4th - keep an eye on the gas gage, a bad sending unit in the take will show up as a "twitchy" needle.

Of course, if the gage never leaves empty - sloshing won't work.
I have a known good sending unit I can plug into the vehicle and simulate different levels of fuel - if the gas gage works, I know the problem is in the tank.

Let us know.

Dave

That may be a sign of a bad alternator. start you car and take the positive batter cable off the battery. If the car dies replace the alternator. That is a really good sign that your alternator is bad.

fuel gage makes wrong readings