Temp gauge starts at "normal range" when cold

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Jan 31, 2007
OK so my temp gauge when the vehicle is off is all the way to the right or "H". When I start the vehicle after its been sitting for a few days, the needle only advances to the "normal operation range" ie in-between the two hashes. As soon as its warm, its reading hot.... thermo scanned engine, thermometer in rad etc, vehicle is not over heating. Changed temp sensor at block, same results. do these needles get "off" the mark? can they be adjusted? can the gauge be serviced? or do I need to just replace....if I can find one.
Replace the temp sending unit. It acts like it has a fault with the internal grounding. I've had this same problem and a new temp sender fixed the problem.
Replaced with new one, same results, ordered a "good" used factory one from spector, same results...gonna try to tweak the gauge, it seem to be only operating from normal range to hot hmm
what year is the rig?

The '69 vintage temp gauge and sender works opposite from the later ones. In other words the sender grounds more when it is cold than when it is hot. The allows more current through the gauge and deflects the needle toward the cold side of the indications.

If the gauge is grounded directly instead of through the sending unit, it will over heat the metal flexor that moves the needle and it will not point as far in the direction that the current is trying to make it move (The cold side of the gauge in this case).

Sounds like that is what has happened to yours. You can open the gauge up and rebend the workings so that the needle points where it should.

Correct me if I'm wrong but the Water temp gauge and the Fuel gauge gets their power (7Volts) from the regulator inside the Fuel gauge.
If anything goes wrong there, the read out of the Water temp (and the Fuel gauge) will be off. See pic below.


So before you start bending, check with a volt meter if you have 7 Volts on the third (top) nut of the Water temp gauge and / or the first nut (right) of the Fuel gauge. See pic below.


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