According to the book it should be #12.
It is located behind the glove box
A Haynes or chiltons manual has the how to. Or do a search for a forum for Chevy corsica specific
Cool the heater hose and then gently take it off
Answerp0137 or p0147 if it's the heater circuit.
In most Chevys you need to remove the dashboard to get to the heater core, a 4 1/2 hour job.
Just unhook the hoses from the heater core and put a tube are something in the middle of them and clamp them together.
Under dash, near firewall, passenger side.
the library should have a shop manual to make copies of for your vehicle...:)
fan motor could be bad