jwc1949gmc,
Welcome to the Stovebolt. I looked at a diagram of your truck...I didn't know they had an electric temp gauge.
The wiring diagram shows the temp gauge power in series with the fuel gauge power...both off the ignition switch. If you have a voltage reducer ahead of the fuel gauge, and the wiring is as I described, you now have TWO reducers in front of the temperature gauge.
If this is actually how the truck is wired, it would make the temp gauge read incorrectly. I would verify the wiring, and for sure would stick with the stock sending unit if you still have it. A new sending unit would probably not be calibrated for the stock temperature gauge, reduced voltage or otherwise.
Stuart
