Dodge Repair: 1999 Ram 1500 heater fan OFF and HIGH only, blower motor resistor, negative cable


Question
QUESTION: The heater/AC fan in the van stopped working properly.  It only blows on high.  On the low and medium speed settings the fan does not blow.  It blows full speed on the high setting.  Is this a bad switch, bad motor, or something else?  How do I determine what needs replacing?

ANSWER: blower motor resistor.

---------- FOLLOW-UP ----------

QUESTION: Thank you for your quick answer.  Where is the resistor and what does it look like?

Answer
REMOVAL
Disconnect and isolate the battery negative cable.
Reach under the passenger side end of the heater-A/C housing and unplug the wire harness connector from the blower motor resistor.
Remove the screws that secure the blower motor resistor to the heater-A/C housing.
Remove the blower motor resistor from the heater-A/C housing Blower Motor Resistor - Typical
INSTALLATION
Install the blower motor resistor into the heater-A/C housing and secure it with the mounting screws. Tighten the mounting screws to 2.2 N·m (20 in. lbs.)
Plug the wire harness connector into the blower motor resistor.
Connect the battery negative cable.