How do you fix the fuel gauge for a1993 Saturn sl?

Answer 1

Possible "easy" fix for "S" series gashttp://www.saturnfans.com/forums

Fuel gage

Re: 93 sl1 fuel gauge don't read can anyone help?

There is no fuse for the gauge. I do not have a schematic for your year so I can not tell you what to check. Go to a decent library and they will have a set of Mitchels books or internet access to the data. Find the schematic and check the tank level sensor back at the tank.OTE: Fuel tank (and gauge) MUST be 3/4 or LESS BEFORE you start this!
What you will need:
I automotive type TEST LIGHT
(Available at Walmart or any autoparts store for less than $10)
EXTREMELY IMPORTANT!! DO NOT make up your own version of this repair! Follow the instructions EXACTLYOpen the trunk
Slip the trim carpet away from side of the DRIVER'S SIDE wheel well and locate the THREE WIRE connector hidden behind it. This connector will have THREE WIRES (Grey, Black with a WHITE stripe, and Purple)
START the car and LEAVE IT RUNNING, make SURE you can see the fuel gauge through the back window easily (recline driver's seat fully)
Connect the clip of the test light cord to GROUND
Probe each of the three wires where they go into the connector QUICKLY, one (but not the other two) should light up the light confirming that it has a good ground. If it does not light up reclip the test light clip somewhere else and repeat until you are SURE you have a GOOD GROUND to the test light.

While observing the gas gauge through the rear window , probe the wires again in the same manner until you find one that when probed causes the gas gauge to peg all the way over to the "FULL" mark.

Leave that wire probed (and the gauge pegged over) for 15 seconds and then remove the probe.

Shut the car off and WAIT about 10 minutes, then restart the car. If you have been successful the gas gauge should now be reading higher than it was before you started. It IMPORTANT!! DO NOT leave the probe connected for longer than the 15 second interval listed! If you do, you may wind up with a gauge that constantly reads too full!!!
Why this works:
Your gas gauge works basically by having two electro magnets fight against each other on either side of the needle. One side gets a basically consistant ground from the wiring harness that is always trying to pull the needle toward the EMPTY the other gets a VARIABLE ground from the sending unit in the gas tank that tries to pull the gauge toward FULL. As the tank empties, the signal from the sending unit gets WEAKER, allowing the EMPTY side of the gauge to gradually "win" this electronic tug of war. As anyone who ever took science in grade school knows, an electro magnet retains a partial magnetic field even when the power is shut off to it. Over time this residual magnetic field will remain/get STRONGER on the magnet that gets the most consistant power feed (the EMPTY side of the gauge) and NOT as strong on the magnet that gets the least consistant (or variable) power feed (the FULL side of the gauge) By giving full ground via this proceedure BRIEFLY to the magnet on the FULL side that normally gets only a partial and variable ground, you are "recharging" the residual magnet field that this magnet has even when the power is shut down to it. This makes it SLIGHTLY easier for the magnet on the FULL side of the gauge to do battle with the magnet on the EMPTY side of the gauge when powered up and in doing so makes the gauge read correctly (or more so) again.