Correct Wiring for Furnace Blower Motor
check resistance from white wire "neutral". To Each wire. The higher the resistance the Lower the speed. Brown wires. "brown, &amp; Brown" with white stripe. usually go to capacitor. (on 120 Volt) motors. 
 Example>>> White to black, check resistance. write it down. white to red, White to Blue. The Higher the resistance, The slower the speed. Black is "generally" HIGH speed. Red Is "generally" the lowest speed. This is NOT always the case. ALWAYS check resistance to verify the proper wiring speed. 
  Cooling mode is "generally" The highest speed. Heat is "generally" medium to Medium HIGH. Depends on the furnace AND the manufacturer specs for HEAT TEMP RISE. Always Check TEMP rise on all blower replacement. 
 Hope this helps..