Replacing the heater or blower motor resistor on your Jeep Wrangler is a quick and easy project that you can do at home in just a few minutes. The resistor is located on the heater and A/C housing under the passenger's side of the dash board. The resistor is basically a group of wires with different resistance within each one. When you switch the fan motor control to a speed on the control, the current gets directed through the proper wire to spin the fan at the selected speed. The resistor cannot be repaired if it fails; it must be replaced.
Open the hood and locate the negative battery terminal. Remove the negative battery cable with a wrench and ensure that it cannot fall back or make contact in any way with the battery.
Open the glove compartment on the passenger's side of the dashboard. Locate and remove the retaining screws around the perimeter of the glove compartment using a screwdriver. Pull the glove compartment out of the dash.
Locate the heater resistor on the bottom of the A/C and heater housing. You need to remove the electrical connector from the resistor by first pulling the locking tab up. Unplug the connector and set it aside for now.
Locate the two mounting screws on the resistor. There is one at each end of the resistor. Remove the screws with a small socket and ratchet and remove the resistor from the housing.
Install the new resistor onto the housing with the original screws. Torque the screws to 20 inch-pounds with a torque wrench.
Connect the electrical connector to the resistor and push down the retaining lock. Replace the glove compartment and tighten all the screws that secure it with a screwdriver.
Reinstall the negative battery cable onto the negative battery post. Tighten the screw on the clamp to secure it. Test the heater blower switch to ensure it is working as intended.
