Hi, I tested my gauge and it goes full Hot when grounded and Cold when disconnected. I measure the sending unit temp with a infrared gun and measured 1.002k ohms at 55 degrees and 195 ohms at 176 degrees. So the gauge and the sending unit are working but I suspect the resistance is wrong. I also checked for 0 ohm between the sensor brass case and chassis ground. 68 like most everything else is one year only since it has a smooth round non threaded stud that the wiring harness pushes on to. I bought the unit off EBay where it stated it was for 57/58 Chevy and 1968 Chevelle and I am starting to doubt the resistance is the same even though the physical connection is the same between the years. BTW my temp gauge read about 1/8 up from Cold at 175 degrees and I suspect it should be at least 1/3 up. Anyone have resistance per temp for a 68 sending unit. Thanks

Well I tested a 69 sending unit and it came in around 110 ohms at 175 degrees which is nearly half the resistance at 175 then the one I have which I bet would work but it has the wrong connection type. I found a unit at Echlers that is USA made and is guaranteed to be accurate for a 68 resistance wise. So when I get it installed I will update this. You gotta love a 68, never a boring day. LOL

If you PM ARK68SS, you will receive he info that you need, including a part #. He helped me out with this a few years back, but that car is gone, and my file went with it.

I ran three temp senders on an Automated temperature Calibration System (In a Glycol Bath) years ago. Here's a summary of the raw data where Rs is the temp sender resistance and a picture of some of the GM style temp senders (origin of picture unknown to me).

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Llectric Limited is the only supplier of a sending unit for the '68 SS that has the factory gauge setup that actually works properly.
www.llectriclimited.com In the picture in the earlier post (that I think came from LL's site) you need the one on the far left.
BillL

Thanks Bill, you are correct. Apparently it's an old picture and I hope they don't mind me posting it here.