FJ40 temperature sender idle resistance reading poll (1 Viewer)

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TexFJ

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So I just installed a brand new temp sender (83420-20011) in my F engine head (3/73), just because it was easy to do and eliminated any ambiguity from the readings.

Not sure what the old sender was and how it mapped per temp. Since I'm not sure I can trust my gauge, i went to the sender to measure resistance. After warming up, it read around 47 Ohms, but the gauge reads above the normal range.

What do you all see at idle?

Screen Shot 2022-04-09 at 12.28.39 PM.png
 
There is a 7v regulator in the fuel gauge that feeds the temperature gauge. If that is failing it can cause both gauges to read high.
 
I was looking at this circuit and started to theorize the issues that could make the readings higher than normal vs. lower than normal.
Thinking out loud: For the temp gauge to read high it would mean the avg. voltage from the Fuel gauge VR would be higher than normal. (not sure if that's 6V or 7V). Debugging this would force me to get a scope to avg out the pulses (those wires are sooo delicate too). I guess if the bimetal strip is now switching irregularly causing the duty cycle to be higher, then there's the problem I guess.

What aftermarket gauges would work with the OEM temp sender? Has anyone done this?

Screen Shot 2022-04-10 at 11.36.37 AM.png
 
OH, and if anyone else has measured their resistance at IDLE, I'd still be curious for comparison.
 

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