It seems to me the cold engine lock out switch is the culprit (located on the thermostat housing). You might want to check to see if the connection/wiring is good. Or replace the that switch.
Here is a procedure to check the blower.
http://www.programainc.com/files/blower_speed_regulators/33910.pdf
http://www.programainc.com/files/31285.pdf
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