OK, if you look at the wiring diagrams, there's no logical way that a bad blower motor switch could create the OP's symptoms. However, a shorted blower ballast resister could.
To test the blower resister with an Ohm meter, verify there is 1.3 Ohm between terminals 4-3. Between 3-4 should be 0.5 Ohm. Between 1-2 should be 0.5 Ohm.
Or just look at it. Usually the rust through or bunt appearance is a dead give away.
I would also double check that the blower runs at full speed if the blower resister #4 (O/BK) is grounded. Be sure to use a solid ground because the blower needs a lot of current. If the blower does not run on full speed, then consider the blower may have bad bearings.
Last edited by wmburns; 06-02-2012 at 09:46 AM.