The blower motor plays a crucial role in the air conditioning system of a Jeep Wrangler. It is responsible for circulating hot or cold air through the AC vents. However, if the blower motor develops a fault, the air will not flow out of the vents when the AC is switched on.
There are several common causes for the AC fan blower motor not working in a Jeep Wrangler. These include a blown fuse, a bad relay, a malfunctioning resistor or control module, a faulty blower motor, a bad electrical connector or broken wire, and a defective climate control unit.
A faulty fuse can interrupt the circuit and prevent the blower motor from working. To check if the fuse is blown, refer to the Jeep Wrangler’s owner’s manual or the fuse box cover for the exact location of the blower motor fuse.
If the fuse is blown, replace it with a new one of the specified amp rating. You can determine if a fuse is blown by examining the metal strip inside it. If the strip is broken in the middle, the fuse needs to be replaced.
Relays are switches used to control electrical loads. A faulty relay can cause the AC blower motor to fail. Consult the vehicle’s owner’s manual to locate the blower motor relay, typically found in the engine compartment or under the steering wheel.
You can test the relay by swapping it with a similar one in the fuse box, but be sure to disconnect the vehicle’s battery before proceeding. Note that vehicles with auto climate control may not have a blower motor relay.
Bad Resistor or Control Module
The blower motor resistor controls the motor’s speed. If the resistor module develops a fault, it can cause the blower motor to stop working. Typically, the resistor is located under the passenger side dashboard, close to the blower motor. Overheating due to a struggling blower motor can cause the resistor to fail. It is recommended to replace both the resistor and the blower motor together.
To test the blower motor resistor, use a multimeter to check the voltage at the electrical connector on the blower motor. If there is no voltage or voltage only at certain fan speed settings, the resistor may be faulty. If the voltage reading is normal, the issue likely lies with the blower motor itself.
Faulty Blower Motor
A broken blower motor can result in no air flowing from the vents or poor and inconsistent airflow. Early signs of blower motor failure include unusual noises, weak airflow, and, in rare cases, a burning plastic odor or smoke when the fan speed is set to high.
To test the blower motor, disconnect the electrical connector and use a multimeter or test light to check the voltage. If the voltage reading is normal, it suggests a fault in the blower motor. For a more accurate test, you can connect the blower motor directly to a 12-volt battery using an alligator clip test cable. If the motor fails to spin, it confirms that the blower motor is defective and should be replaced.
Blower motors can last over 10 years, but factors like overheating, moisture damage, or manufacturing defects can cause them to fail earlier. Listen for unusual noises as a potential warning sign of impending blower motor failure.
Bad Connector or Broken Wire
A faulty connector or broken wire in the blower motor, resistor module, or climate control unit can disrupt the power supply to the blower motor.
Rodent damage is another possible cause. Rodents can chew on wire coatings, leading to electrical issues. Inspect all cables and hoses for damage, including the blower motor’s electrical wires, if rodent damage is suspected.
Defective Climate Control Unit
In rare cases, a fault in the climate control unit can impact the blower motor’s performance. The climate control module is responsible for controlling the blower motor’s speed and overall operation.
In conclusion, when troubleshooting a non-working AC blower motor in a Jeep Wrangler, it is advisable to start by checking the most obvious causes such as blown fuses or faulty relays. However, it is recommended for non-experts to seek professional assistance to avoid causing further damage to the vehicle’s electrical system. A qualified mechanic can quickly diagnose and address the issue.