In most cases, the blower motor resistor has failed if the fan only runs on high. The resistor is located on the passenger side of the plenum assembly behind the glove compartment.
I attached two pics below. The first shows a general location of the resister. Pic 2 shows what the resistor looks like.
All you need to do is remove the connector and then the two screws which hold it on the plenum. Pull it straight out. The installation is the reverse of removal.
I hope this helps. Let me know if you have other questions.
See pics below.
Images (Click to enlarge)
Monday, April 19th, 2021 AT 3:18 PM