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I would like to test the fuel and temp gauges from my '64 before reinstalling them in the dash cluster. I know that the constant voltage regulator provides a pulse that averages out to about 5.5 volts. My questions is, if I apply 5.5 volts directly to the studs on the back of each gauge (temp and fuel), will I be able to see the needles move? Or should I apply 12 volts for an instant to simulate a pulse? BOTTOM LINE: What is the best way to test the temp and fuel gauges outside the car? I have lots of tools, just need advice on technique. Thank you.
 

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Hook two (2) D cell batteries to the two posts. Gauge should read about 1/2 way if it's good.
 

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You can test for full deflection, adjust for reading, and adjust your gauges to zero on the bench. But the fuel gauge should be adjusted with the sender in-tank for accuracy with that sender.

Pull your gauge to adjust it. There are two holes in the back of the gauge. One slightly closer to the center or studs than the other, and is closest to the needle pivot point. Adjust in that hole first with no power to the gauge to set gauge "zero". The adjustment is made with a small flat screwdriver blade to tweak the little teeth in the hole to each side.

You can rig your car's IVR (instrument voltage regulator) with a 12V battery on the bench, along with your sensor/sender, giving the gauge voltage your gauges will actually see. Else, test with a 5.5-5.7V setup. Then adjust the outer hole (closer to the needle tip) with signal to the gauge (power through the sender) to set the current actual reading. Re-test both settings (one will somewhat affect the other) and re-assemble.

With your engine temp gauge, I suggest you set the high-end (pegged at overheat) with your sender heated to 40° to 50°F above your thermostat rating. This is the actual risk-of-damage range. Some folks set the gauge to read their 'normal' running temp at center, but keep in-mind that setting affects if and at what temp the gauge hits 'hot'. Your basic gauges all work pretty much the same (except ammeters and tach's) and can be adjusted similarly.

David

PS: These gauges are not linear, so half scale is not half temp or whatever, and each gauge and sender is different. Normally, you would set the end values, and the middle is wherever it sits in operation.
 
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