Did you do any of this?1)Did you run these tests to determine actual cooling system temp?
a)With the car at idle at what temp/voltage does the cooling fan come on?
b)With the car at idle at what temp/voltage does the cooling fan shut off?
c)When the cooling fan cycles on, what is the gauge in the car reading?
2)Have you run the cluster self test?
View attachment 272681
3)The electronic instrument cluster is BCM controlled, do you have access to a scan tool that will allow you to access Engine Data and the BCM?
4)The engine temperature sending unit is only a variable resistor to ground for the gauge.
On an analog gauge if you remove the wire from the sending unit and connect a jumper wire from the sender connector to ground with the key on the gauge will read Full/Max Hot.
It should work the same way with the Electronic Cluster.
This will tell you if the wiring is OK from the sending unit to the cluster and if the gauge itself is functioning.