Both, low level and temp sensor, are somehow linked via relay3.

Low level is only connected to relay 3, still can trigger the LED. So
pin4 of relay 3 seems to be an output for the LED.
Instead of being connected to the LED directly, it loops back into the
temp signal from G2 (fusebox K4 -> D29).

The temp gauge on the wiring diagram is also shown to include some kind
of controller,
My assumption: The LED might be triggered by pulsed "high temp" values
coming from relay3. Maybe, these are not long enough to make the needle
move.
Isn´t that the purpose: Showing low coolant albeit correct temp.

My tip: Replace/pull relay3. Then continue test on the low level sensor
line.

Raimund
P.S: As a german I am proud of myself remembering how to use "albeit"

Am 22.04.2022 um 22:06 schrieb OlRivrRat:
>         Seriously? Who ever heard of such?
>
> I’m hoping that 1 of Our Vanagon Electrical Wizards has the answer to this 1 ~
>
> Temp 1 Sensor providing accurate reading on Temp Gauge but LED Blinks,, Make
>
> darn sure that Connection to T’1 Snsr is as good as can be (quite by accident) &
>
> LED Stops Blinking & works as it Should ~
>
>         What could be wrong with that connection that cause LED to Blink while still
>
> providing Accurate Temp Data to the Gauge??
>
>          & part of question that I forgot to ask > Why would the Temp 1 Snsr have
>
> any influence on the LowLevel LED ~