Trans Temp gauge doesn't read temp.

[ShawnCT450R]

Aftermarket trans temp gauge doesn't show the temp of the transmission oil. It's in a three gauge cluster on the A-pillar. All three gauges perform the "start-up check" just fine, and all three gauges are illuminted as they should. Not sure if it's a faulty connection, or if the temp sensor thats screwed into the side of the tranny is bad. The connections appear to be plugged in right, and tight. Any ideas? If I do a resistance check of the sensor to see if it's bad, what would the acceptable spec be? It hasn't worked in along time. Just getting around to looking at it. Thanks in advance.

[dhanna6powerstroke]

It won't show anything for quite a while, especially if it's cold out. I towed about 10k, 230 miles last weekend and mine never got to 140*.

[ShawnCT450R]

It hasn't work for a very long time. I recently towed 18k across country, and all I got from that gauge was some illumination while it was dark outside. hehe.

[Lilpooh]

What brand gauges?? I know Autometer has a write up on testing temp sending units.

[AR Aggie]

If you can't find the resistance test guidelines for that brand gauge, I would take a resistance measurement while it is cold then again after/during your next trip. If the resistance changes I would look at the gauge first. However, I bet that gauge manufacturer's tech support has the measurements you should see.