Change from Digital to Analog?

[superhawk996]

The engine coolant temp sensor used with the analog dash vs. the engine coolant temp sensor used with the digital dash, which also sends that temperature info to the ECU for fan management and probably/possibly engine management.

[nomadicdread]

7 minutes ago, superhawk996 said:

The engine coolant temp sensor used with the analog dash vs. the engine coolant temp sensor used with the digital dash, which also sends that temperature info to the ECU for fan management and probably/possibly engine management.

Thank you for clarifying. 
So the analog temp gauge working comes down to the resistance of the coolant temp sensor? And if only the resistance at the gauge is changed, then it could possibly be made to work within range?

[superhawk996]

There's no reason the analog gauge could't work with the digital dash's sensor, as long as you can modify the signal to the gauge.  I don't know electrical shit well enough to say how, but it 'should' be doable.  Anything more complex than adding a resistor and I can't help.  But I think a resistor in the sensor lead or the power lead would let you compensate for higher or lower resistance sensors so it might be fairly simple.  The sweep might not be normal as compared to a stocker with analog, but once you know what the normal temps register on the gauge it wouldn't really matter.

[nomadicdread]

I looked online at the service manual for the temp coolant sensor:

At 168F

'99 should be 47.5-56.8 k ohms
After '99 should be 2.1-2.6 k ohms

 

At 248F

'99 should be 14.9-17.3 k ohms

After '99 should be .62-.76 k ohms

[superhawk996]

A possible solution is to put in a T fitting or drill & tap threads for a second sensor and run a bypass wire from the analog sender to the gauge.

 

I rethought my 'resistor in the power lead' idea and I'm pretty sure it would have the same effect as putting it in the sensor lead so I'm pretty sure you can scrap that idea.  My guess is that the digital dash sensor has a higher resistance (weaker, lower voltage/current) signal so you'd have to find a way to boost the signal for it to work with an analog gauge.  Guessing based on an analog gauge needing more current to operate than a digital, but it doesn't mean they didn't go the other way around for some reason.  If the digital gauge sensor has a lower resistance then all you'd need is the right resistor to make the analog gauge work.