cooling fan switch

I live in a V. HOT climate ( ME) and i have a car "( GM cavalier 97 ) . the fan open at 100*C and off at 90*C i wont to change the cooling fan switch to open at 80*C or less .the resistance of the ( cts) for my car
100*C 177 OHMS
90*C 241
80*C 332
70*C 467
60*C 667
50*C 973
40*C 1459
30*C 2238
20*C 3520
10*C 5670
0*C 9420