Measuring temperature with Multimeter

[AZ4x4]

I've seen people use multimeters to verify their temperature at the sending unit. Does anyone know the formula I would use to do that? I'm interested in finding out if my temperature is accurate at my temp gauge. Thank you.

 

[JAFO]

Found this old thread...

http://classicbroncos.com/forums/showthread.php?t=206739

But it seems to be just testing the gauge. Looking around for the sender info....

So, this appears to be the part number for the correct sender...

http://www.napaonline.com/napa/en/p/ECHTS6153

And the specs state-
Temp Sender Switch Temp Rating C At 100°F 125 Ohms w/ 15% Tol, O At 220°F 17.12 Ohms w/ 7% Tol

So, if you were to measure the resistance from the terminal on the unit to ground it should be somewhere between those values. Probably not linear though. Would be nice to find a complete table for that sensor.

 

[ren71]

not an answer to your question but, IR temperature guns are extremely cheap nowadays, like $10 cheap on amazon or less than 20 at harbor freight etc.
They seem to be pretty accurate and very handy for other things like grilling etc.

 

[dave67fd]

Would be nice to find a complete table for that sensor.

Would be easy enough to do by putting the sensor in water with a reasonably acurate temperature gauge and an acurate (fine adjustment) heat source. Measure the resistance for every 10-20 deg. rise and do 0-300 deg. range. With some graph paper you can plot all the points. Would give you a good idea how linear it is.

 

[Steve83]

Here's the formula:
http://www.amazon.com/dp/B00JA3BMDW/

 

[smokinjoe]

Seriously man, you need to consider some mechanical gauges if you are this concerned about it. http://classicbroncos.com/forums/showthread.php?t=265857 OE gauges aren't dead on accurate anyway IMO, not a huge upgrade over an idiot light.