If my truck has a temp gauge does the temp light function?

[Rich69shortfleet]

My truck has a factory temperature gauge. I have converted all my dash lights to LEDs. LEDs only work in one orientation so you need to test each light to make sure the bulb is in in the correct orientation. To test the brake warning light I shorted the wire at the brake valve to ground and the dash brake light illuminated. Since my truck has a temp gauge I don't know if the TEMP warning light is even connected to anything. If so, where is it connected? I tried grounding the temp sending unit wire and the light didn't illuminate so I'm guessing it either isn't used or is controlled in some other way.

Also, the TEMP light does not illuminate when cranking which is usually when it is tested with a working light so again, I'm not sure it is even used on a truck with a gauge.