Serpentine belt and temp gauge

Hello and thanks for the help (I know nothing about repairing anything). I have two questions about my 1997 dodge ram 1500 v8 magnum 140,000miles, 5.9 360. 4x4 (Centruion special edition)

Question 1) I reciently bought the truck and when I start it about 90% of the time there is a squeeking noise comming from the engine (it squeeks repetidly). I took it in (repair shop) and he replaced my cerpintine belt and I left and now a month or so later its back to the squeeking. My friend said spray it with like a WD40 and true the squeek does go away but only for a day or so. Any suggestions to a perminante fix?

Question 2) My dodge also has on the inside on the top console and gauge that digitaly says the direction and temp of outside. The North South East West works like a charm but the temp will do a few things.A) not say anything B) give me the wrong temp (random temp not even close). I tried to reset it and do the 2 360 turns in under 60 sec but that doesnt work and I think that is to reset the directional unit anyways though. Anyone know how to help?

Thank you again and sorry for my bad spelling also.