03 Jeep, Blend door have been replaced last year and work fine, blower motor resistor just replaced and now works fine, but now there is very little air flow form any of the vents, is there another co

There are several possible reasons why your blower, vent, defrost, AC, and heater might stop blowing air:

1. Blower Motor Failure: The blower motor is responsible for blowing the air through the vents. If the blower motor fails, you will not get any airflow from the vents.
2. Blower Motor Resistor Failure: The blower motor resistor controls the speed of the blower motor. If the resistor fails, the blower motor may stop working or only work at one speed.
3. Fuse or Relay Failure: A blown fuse or faulty relay in the blower motor circuit can prevent the blower motor from working.
4. Control Module Failure: The HVAC (heating, ventilation, and air conditioning) control module is responsible for controlling the blower motor and other components. If the control module fails, it can prevent the blower motor from working.
5. Vacuum Leak: If your vehicle uses a vacuum system to control the vents, a vacuum leak can prevent the system from working properly.
6. Broken Blend Door: The blend door controls the direction of the airflow. If the blend door breaks or gets stuck, the air may not flow through the correct vents.
7. Wiring or Connector Issues: Faulty wiring or connectors in the blower motor circuit can prevent the blower motor from working.

The resistor bank is bad for slow speeds, the switch is bad for high speed. In your test, you have voltage, but the switch wont carry the amps, to run high speed. Open circuits will not blow fuses. Replace both switch and resistor bank for all speeds. Make sure to clean leaves and trash from fan housing and see if fan spins freely.

Hi there:
First I suggest to check is to be sure that the blower motor has power to it, it should have power directly to the blower motor. The ground is controlled by the resistor and the a/c switch assembly, if there's no power, then you need to check all the fuses. If there is power, then you can ground the black wire from the blower motor directly to a good ground and see if the blower works at high speed, if it doesn't operate, then the blower motor is bad and needs to be replaced, if it does, then you need to chase the ground wire through the resistor and to the switch.


You may still find the resistor blown, if so, replace it, be sure to replace the motor also, many times, a motor that is drawing too much current will cause a resistor to fail. If the resistor is ok then either the switch is bad or the ground is bad, you may have to manually follow the wires to find the ground point.


HERE is the Jeep flow chart...







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Is the blower running at full speed? Did you check the blower motor resistor?

Maybe bad blend door

thats is two different problems. the blower motor resistor is bad causing it not to work on the lower setting just high. now on the defrost not working could be the blend door actuator but to figure it out you will need to be diagnosed by a professional. it is a little more involved. but the blower resistor is fairly easy

let me know if you have any ore question

2 problems?
No blower motor: Blower motor resistor very common or motor itself or heater controls.
No heat: Start simple with check antifreeze level after vehicle has sat for a few hours. If that's OK then it could be thermostat, heater controls, blend doors, water pump, restriction in cooling system

The Blower Motor Resistor is a common problem in your car but not for the problem you describe. When the Heat/AC won't blow on all speeds, the blower motor resistor is at fault. When air won't blow out of vents, bi-level, or floor the problem is the blend door actuator. This is vacuum driven and diverts the air to where you select. When air will only blow from one place (usually the defrost) then the blend door actuator is the problem. This can sometimes be corrected if there's a vacuum leak (usually under the hood in front of the passenger you'll find the vacuum line and can trace it backward to find a leak). If no leak can be found, the blend door actuator itself is defective and needs replacement.

Your blower motor resistor has gone bad. Everytime these go out (definitely happens a lot on Jeep) you will lose every speed except for the highest one. Replace your resistor and you will be back to new. Let me know if you have any further questions. Thanks for using FixYa!

There is a 30 amp fuse for the blower. The blower motor resistor could be bad.