Instrument cluster testing

Without "being there" or having a fuel gauge to dissect, there are some caveats..........but look above in this thread.............if you put 3V directly across one gauge, it should read close to full scale as shown in one of the photos near the top of the thread.

The trick would be to "get into" the fuel gauge and cut out the bad IVR so it doesn't short or cause problems for testing or replacement.

So far as the other two gauges, if you simply remove the nut on the fuel gauge where the black plastic cap is, that will electrically isolate the other two gauges.

For example look at the photo below with the added black markings

Remove the black plastic as shown and the nut below it

Hook 2 flashlight batteries in series (3 volts) to the two marked "3v oil" to check the oil gauge, leave them on for 30 sec. or so. The gauges should go "not quite" to full but should not peg

Likewise to check the temp gauge, apply your 3V to the two marked "T"

You cannot check the fuel until you successfully get the old IVR disconnected.

There are folks who rebuild them. I believe "Redfish" does that work.