99 Civic Fuel Level Gauge Stuck on Full

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#31

10-29-2013, 04:36 AM

alpinegroove

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Thanks for the info. Do I do that with the ignition set to ON or OFF?

#32

10-29-2013, 04:39 AM

RonJ

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...Off

#33

10-29-2013, 06:21 AM

mk378

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Whenever you use the ohms scale on the meter, the power to the circuit being tested must be off. Otherwise you get incorrect results at the least.

#34

10-29-2013, 04:52 PM

alpinegroove

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Quote:

Originally Posted by mk378

If you pull the cluster, first check if the wire is shorted to ground, should be open circuit. Then plug the tank back in and measure resistance from the wire at the cluster plug to ground again, testing all the way through the circuit. Depending on how much gas is in the tank, it should be somewhere between about zero ohms (tank full) and 40 ohms (tank empty). If that checks out, the cluster must be bad.

I unplugged the sending unit and the cluster and tested the Yel/Blk wire. No continuity to ground.

I plugged the sending unit back in and measured resistance from the Yel/Blk wire at the cluster to ground (a black wire at the cluster). The numbers were fluctuating between 39.5 to 41 ohms. My multimeter was set to Ohms 200. The tank is almost empty.

So does that mean that the sending unit and wiring to the cluster are fine, suggesting that the problem is in the cluster itself?

What's the next step?

#35

10-29-2013, 05:11 PM

mk378

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Check that the screws holding the fuel gauge to the printed circuit of the cluster are tight, as they are also the electrical connections. It sounds like the gauge is bad though, so then you're looking to replace the cluster, or at least the fuel gauge part of it.