All my gauges except fuel gauge (fuel gauge worked fine) were acting weird. Sometimes they worked, sometimes they were all over the place. So I checked all fuses under the dash and under the hood. All were fine. I removed the instrument cluster and disassembled it. Cleaned all contacts on back with bulbs and screws removed. Put everything back and reinstalled instrument cluster. Now everything works perfect but fuel gauge slowly moved to full and its stuck there. My tank is only half full. What should I do to fix this. Also any advice on properly testing gauges and handling instrument clusters. All I know is I've been told to never touch the face of instrument cluster with bare hands due to static in your body could short it out.

 

The fuel gauge only has 3 connections. power, ground and the signal from the tank sending unit. It Shares power and ground with the other gauges so if the other gauges are working the power and ground are prob good and you should focus on the signal. It gets signal from the sending unit from pin 12 (yellow/white wire) so check for continuity form the pigtail at the cluster to the tank sending unit. The sending unit works of resistance to ground. about 110 ohms empty and about 5 ohms full. So if you have half a tank you should be in the 40ish ohms to ground at the sending unit.

 

Also I have heard, multiple times, that you can easily over tighten the holding screws on the gauges and it causes the gauge problems.

Every time I've messed with a gauge I've lightly snugged the holding screws to avoid issues.

 

i recommend swapping fuel guage from another car. had same issue couple years ago on a eg coupe

 

I can almost guaranteed you've done this:

• Reassemble the fuel/temp gauge into the cluster housing BUT DO NOT OVER TIGHTEN THE SCREWS. THE GAUGE IS VERY SUSCEPTIBLE TO DAMAGE! The tiny wires that are in the gauge can be torn/broken by over-tightening. I've done this before and it is NOT A FUN REPAIR. BE VERY CAREFUL. I recommend you hand-tighten the 6 screws on the back of the fuel/temp gauge and just use a screwdriver to tighten a ¼ or ½ turn.

.... this is from my Low Fuel Indicator Retrofit DIY.