It's possible your blower motor will only work on high speed. High speed doesn't use a resistor, the lower speeds do. Lower speed lower voltage if you want to word it that way.
Check for voltage and ground at blower motor connector, lower speeds.
If you can't push buttons on hvac control module, it may need to be replaced?
The top four wires in diagram are for lower speeds. The yellow wire is for lowest speed. With hvac turned on lowest speed, any voltage on the wire? The lower speeds use a different fuse than the high speed.
Friday, November 7th, 2014 AT 11:21 AM