Is it possible he pin connection could be shorted to each other (visual inspection)? Check continuity from the pin to pin, should be infinity.

 

It’s a single wire and I replaced the connector.
I thought that I may not be getting a good ground so I clamped a 6AWG wire to the outer casing to a good ground and it still pegged out.
with the ignition on, the gauge goes to around 230. Start it and it immediately pegs out

 

So, is,was this a single green wire from the sending unit front driver side to the dash gauge? Is the temp gauge you are refferincing to low left on the dash?

 

Yes it was a single green wire on the left side (drivers side). The temperature gauge is bottom right on the dash

 

https://www.americanautowire.com/vie...oubleshooting/

 

Does anyone know what the resistance should be at the connector?

 

Going out on a limb, I think the wire should be battery voltage to the sending unit. I believe the way it works as the temperature rises, it increases the resistance, drops the voltage to the gauge, and that should correspond to temperature.

 

I could be backwards, if you have the sending unit out, check resistance cold, then put it in hot water, check the resistance, it could be as it heats up the resistance drops.

 

Finally fixed the problem!
after connecting a 150 ohm resistor to verify the gauge should read 210 - 220 degrees ( which it did) that proved that the connector to and including the gauge works as it should, I bought a 3rd sending unit and it’s reading correct. Verified it with an infrared thermometer.

Thanks for the help everyone!

 

Glad it's fixed. I know well the frustration of a "new" part that isn't any good.