Cooalnt temp gauge

[BLKF250]

hey guys i was driving home last night from a friends house and i drove the truck all day and it was fine but the ride home last night my coolant temp gauge took longer then usually to get to operating temp but the truck was driving awesome like it was at operating temp. Then the gauge went up to operating as i was driving then after a little bit it went back down a little i have full coolant no leaks do i need to replace the temp sensor or the therosat? it was like 85 degrees ( all day) then it dropped to 70degrees on the way home when i was driving it at night trucsk has 140k on it

[06 KR]

Is this an aftermarket gauge or the stock one. If its after market then check the grounds and that the sending unit is not loose. Could also be a faulty gauge. How long have you had it in. My autometers lasted about a year then maybe a year after that. I yarded all the well known names and went with someone else. They wanted me to send them the gauge and test it then try it and all that garbage. Anyway sorry for the rant. I would say sender loose or bad ground, other then that bad gauge.

[BLKF250]

Its the factory gauge on the display

[06 KR]

I would say then its in the cluster itself. My coolant temp goes to one spot and stays all the time besides warm up. even when my pillar gauge differs 40-50 degrees my stock one stays the same. So even if your motor is going up and down in temp, it does not register on the gauge. Thats at least with mine and my dads anyway.

[BLKF250]

my truck usually runs from 180 to 195 degrees hook both upper and lower coolant hoses were hot so i new it was getting good flow but on my laptop it said only 145 degrees. My next step was the wiring harness and thats what it was by the connector soon as i touch the wiring harness the temp gauge went straight up to normal and the computer read 180 at idle so fix the wiring everything looking good...thanks for the help