blower fan only works on high

If this has a resistor, than it appears the resistor is bad, because on high speed it is the only speed that does not go through the resistor but to be sure, I will look it up.
Yeah, if this has a manual AC/heat then it does have that resistor. Check for voltage in and out of it when moving the control fan speeds from low to m1 and m2.

Any idea where the resistor would be?

The blower motor resistor is mounted to the bottom of the HVAC housing, below the glove box. The blower motor resistor consists of a molded plastic mounting plate (1) with an integral wire connector receptacle (2). Behind the mounting plate are resistors contained within a metal heat sink (3).
Installation:

1.Position the blower motor resistor (3) into the HVAC housing (2).


2.Install the two screws (1) that secure the blower motor resistor to the HVAC housing. Tighten the screws to 1.1 N·m (10 in. lbs.).


3.Connect the HVAC wire harness connector (4) to the blower motor resistor.


4.Reconnect the negative battery cable.