profourm fan help

[surfsup]

I bought the profourm fan for my mustang and there seems to be a big difference between my engine temp reading and the radiator reading, about a 30 degree difference, my temp reads around 210 before the fan kicks on which is set at the lowest setting of 180. the fans sending unit is a copper wire that sits against the radiator, is there a way to change this sender some how, or rewire the fan and tie this into my sending unit in the manifold, I know there’s several types of two post senders I can buy, but my gauge is an autometer and it uses its Owen special sending unit. I sent an e-mail to profourm but haven't heard anything.