My temperature gauge hasn't been working for several months. on 2005 Chevrolet Impala

My mechanic says its not overheating but is probably a sensor or the gauge itself. He doesn't seem to want to find out which. How do I find out why it isn't working.

Asked by for the 2005 Chevrolet Impala
2 answers
Best to use a scanner to see the actual sensor reading and then compare that with the gauge reading, in order to isolate where the problem is. I do NOT mean a parts store mini-scan, I mean a real Pro level scan tool that can read the data input-output from you engine and instrument panel, not just codes.
I recommend going to a shop with Technicians who know this stuff, your mechanic is either lazy or does not know, neither of which is a good situation.

here are some shops:

https://repairpal.com/directory?address=91006&car_brand_names=Chevrolet
FIRE YOUR MECHANNIC FIRST SECOND...WHEN DOES YOUR TEMP COME ON? WHEN DRIVING FOR LONG TIME>?,WHEN YOU FIRST DRIVE IT? OR TRY USING A TOP RATE SCANNER..THAT WILL SOLVE ALL YOUR PROBLEMS.