Temp Guage issues

Ok here is what I have, please review pics and let me know cause I'm really lost know
1st picture is what was attached to the back of the temp guage and mounted on the back of the dash (what is it and what should it read or do)
2nd front of my temp guage
3rd back of temp guage arrows show where item 1 is located and back of guage states 12V
4th better picture of back of Temp guage
5th show an area where the metal strip has come off the board. I would like to know if might be the cause of my issues. the metal strip is not broken and how/ what can I use to glue it back down. the strip is attached to back guage lights
thanks for any help