u/Aggressive-Cicada222

I do auto school and we had a donation from the county to work on their Humvee, It is a 2009 with a 6.5 NA diesel. The issue i am expiriencing is the gauge wont read the coolant temp, so then we check wether or not the gauge is broken and its not so then we assumed it would either be the wiring to the sensor or oneof the sensors. I feel like i am missing something and I cant find any info, wondering if there is like a common issue or something. All th context ik is that it used to be a military vechile and now its disaster control