as alluded to and stated:
your wiring harness is likely shot, but you are out of luck.. replacement in its entireity is costly and labor intensive on your own, as well.
the overheating needle but "won't get hot" (I assume no hot air from vents is what you mean) is ENTIRELY indicative of a failed waterpump.
replace the pump impellar housing, piece together the (what you will find to be) shattered black impellar. make sure you aren't missing any pieces from those you find in the housing, etc.
If you find them all, toss the new impellar (white plastic!! its the cheapest and proven to not fail in this manner as these do..) in the car, and perform a compression test to see if the overheating has warped the soft aluminum heads, etc.
If you can't piece the entire impellar together, perform a cooling system flush with the housing still off, etc. then replace and do the compression test.
If you have a V6, also keep your engine oil to 6.0-6.5 (I recommend 6.5) qts, instead of 5.8 as the manual states. period. don't worry about overfilling.. don't worry about if this is "safe".. just do this.
