Where wiring schematics are concerned the Haynes & the Chiltons aren't worth the paper they're printed on......the only manual with detailed schematics is the GM factory manuals.
It sounds as tho the blower motor relay (located in the component center) has possibly fused closed on the switch side. You would have to go into the component centre & pull the relay, that should shut down the blower motor.
*Where is the Component Centre* you ask?
...under the instrument panel, centre located, would be on top of the HVAC box.
If you're not accustomed to electrical work you might get some help, a meter would be useful along with a test light.