Problem with Fuel Gauge...need advice

Hello all,
I recently had a new fuel pump put in my 90 4.0L XJ and my fuel gauge is not working. I took it back to the shop that installed and they supposedly checked it out with another gauge which worked so they
thought it was my gauge.
I went to the junkyard and got 2 fuel gauges from a 90 and an 88 XJ. I pulled out my instrument cluster and installed them and nothing....the gauge goes all the way past Full to horizontal! I pulled the connector from the sending unit and it did not go to Full as it should, and then I read an Alldata that the harness wires #15 and 17 should read 0-88 ohms and it did. The only thing I can think now is that the plastic circuit board thing on the back of the cluster is bad.
I am thinking about taking it to the dealer but that could be $$$$$. I have also contemplated getting a whole cluster from another rig and trying that.
Any suggestions would be appreciated.
Thanks,
LTK
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On 24 Sep 2006 00:16:49 -0700, snipped-for-privacy@gmail.com wrote:

It could be a bad connection at the sending unit. - Regards Gordie
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On Sun, 24 Sep 2006 08:28:09 -0400, The Nolalu Barn Owl <&#103&#111&#114&#100&#105&#101&#64&#110&#111&#108&#97&#108&#117&#46&#111&#110&#46&#99&#97> wrote:

or even the sending unit itself. ----------------- TheSnoMan.com
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<&#103&#111&#114&#100&#105&#101&#64&#110&#111&#108&#97&#108&#117&#46&#111&#110&#46&#99&#97>
He said the resistance was correct. Look: I read an Alldata that the harness wires #15 and 17 should read 0-88 ohms and it did." That is the check for the sender. He has a different problem and I do not have a manual for a 90. But I do have the factory service manual for a 91 if it's the same?? If it has an Instrument Voltage Regulator (IVR) that's where I'd start.
LTK,
Didi you do the voltage checks? Or, are the voltage checks in the Alldata info you have?
Al
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The problem with restances and impedance is that it can vary with circuit load particulalrly when a wiper contact is involved. It is quite possibly that the connection breaks down at a certain current level because the meter will present a different load than gage will. This is not to say that it is bad for sure but I would not rule it out because sending units fail far more often than gages do. I do agree that he should check to see if proper voltage is being applied to bridge circuit that the gage is connected to to display fuel level. Very minute amouts of current are invovled here and it does not take much to redure one inop ----------------- TheSnoMan.com
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