coolant fan wiring

i have an 84 camaro that i've installed a electric cooling fan on and need to know how to wire the fan up to run without using a switch. anyone have a wiring diag. that would show how to use a selenoid and temp sensor to run?
also am wiring in a new alternator and need to know how to rebuild , check , a 105 amp alternator. the wiring to the alt. also has been modified by cutting and splicing so much that it is useless. how would you revire it properly?