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Fuel gauge does not work. Replaced sending unit, no help. What next?

Tiny
L IZER
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  • 1993 PLYMOUTH SUNDANCE
  • 61,000 MILES
Fuel gauge went from half to empty when I drifted into a rut and the car rocked back and forth several times.
will gladly make donation after working repair. Got duped on sending unit advice from another website.
Wednesday, September 28th, 2011 AT 6:04 PM

16 Replies

Tiny
JDL
  • MECHANIC
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Do a little testing at the wiring connector for the sending unit. I haven't looked at your wiring, yet. Usually you can use a couple of resistors, wiring connector unpluged, use resistors on sending unit wire terminals. Key on, see if gage will react differently to different resistors?

There is nothing wrong with saying the sending unit COULD be faulty. Your the one that needs to do the testing. We can't see much from here, only make suggestions.
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Wednesday, September 28th, 2011 AT 6:19 PM
Tiny
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In the diagram below, dark blue wire is voltage. The other wire is ground. With key on, any voltage on the blue wire, use voltage tester?
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Wednesday, September 28th, 2011 AT 6:30 PM
Tiny
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Thanks for your speedy response!Your right JDL.I should have found out how to test the sending unit before replacing. All I have is a 12 volt light tester. I clipped my tester to a good ground and probed both wires and found no voltage.I do not understand testing with resistors.
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Friday, September 30th, 2011 AT 1:09 AM
Tiny
JDL
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If no voltage, using a resistor won't show anything. You need to check circuits at your instrument cluster. In the diagram, see the two black dots under the fuel gage, that is ref voltage and ground. Some of thses circuits are shared by other gages. So a problem there should effect more than one gage. You see the one wire with no black dot, that goes to your sending unit. Your sending unit controls resistence to ground, depending on fluid level in tank.

Could be problem with gage itself or wiring circuit.
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Friday, September 30th, 2011 AT 9:32 PM
Tiny
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You did check for voltage with the key on, correct?
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Friday, September 30th, 2011 AT 9:34 PM
Tiny
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Yes check was made with key on. All other gauges and indicator lights work normally, so fuel gauge is probably bad? Several times when I turned on ign I see the gauge move slightly down to the empty peg.I will have to figure how to get instrument cluster apart without destroying to test for reference voltage. Will get back to you JDL when I have accomlished this, Thanks!
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Saturday, October 1st, 2011 AT 6:21 PM
Tiny
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Let us know what you find.
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Saturday, October 1st, 2011 AT 6:31 PM
Tiny
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Hello JDL!Sorry for the delay. Bought a digital volt meter. Got the instrument cluster apart, the ref voltage was 11.8, now what?
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Wednesday, November 2nd, 2011 AT 12:44 AM
Tiny
JDL
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At terminal B at the cluster connector, you have voltage? Backprobe the connector.
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Wednesday, November 16th, 2011 AT 8:57 PM
Tiny
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Hey JDL!Good to hear from you. When I removed the face of the cluster I saw three screws in the face of the fuel gauge.I removed these screws and the gauge pulled right out of the cluster.I grounded the black probe of my tester to a screw in the dash and probed the three holes from which the gauge unplugged. One of the holes had the 11.8 volts the others nothing.I figured this must be the ref voltage you were asking for.I see on the diagram the conn 2 with lettered wires. Where do I find the cluster connector?
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Saturday, November 19th, 2011 AT 2:38 AM
Tiny
JDL
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If I understand your post correctly, I'd replace the dark blue wire from the gage to sending unit.
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Saturday, November 19th, 2011 AT 4:26 PM
Tiny
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I can't rule out the gage, itself, at the moment.
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Saturday, November 19th, 2011 AT 4:30 PM
Tiny
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Hey JDL!I removed the gauge from the cluster not the cluster from the dash. Is the connector on the cluster?Is there a way to test the dk blue wire replacing looks like a lot of work?If the gauge is bad where would I look for a replacement?I got the sending unit from Spectra but I did not see gauges.
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Monday, November 21st, 2011 AT 3:24 PM
Tiny
JDL
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Just leave a pig-tail long enough so you can splice the old wire back if needed. This is just for testing, clip the proper wire at the gage, clip the proper wire at the sending unit, run the test wire from the gage pigtail to sending unit pigtail, let the new wire lay on the ground. See if gage will work, if it does, then you route the new route wire. If it still doesn't work, then you replace the gage. I can't see much from here? You need to know if the wiring circuit is the problem, first?
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Monday, November 21st, 2011 AT 5:47 PM
Tiny
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Hey JDL!Got the gauge working, sort of!Removed instrument cluster, found connector, located dk blue wire. After unplugging sending unit applied 12 volt to wire at connector. With test light checked for voltage at sending unit plug. Had none. Followed wire to rubber plug in floor pan, found broken wire. This was just dumb luck. Repaired wire, plugged everything back togather and gauge worked, sort of.I know tank is only about half full yet gauge reads near full and has for several days of use. But thanks for your help.I will make that donatation as promised.
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Friday, December 2nd, 2011 AT 2:37 AM
Tiny
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Hope you have it going your way. Thanks for the donation.
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Friday, December 2nd, 2011 AT 2:54 AM

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