1990 Corvete Tuned Port Overheating

Hello to all.

My problem is this: the cooling fans do not come on when they are supposed to. When I disconnect the fan swith from the connector on the engine, the fans come on. The "service engine soon" light comes on when I do this.
I have changed the fan switch with the same outcome.

What is causing this? Any and all sugesstions are welcomed.
Thank you in advance.

Have a happy New Year.

ulremember aka Chuck

Can dig the pic, anyway the fans do not come on till 222 degrees, don't know if you know that, but get a scanner on it and see at what temp they kick in if they do of course.