2004 Dodge Dakota Heather blower speeds

2004 DODGE DAKOTA
110,000 MILES • V8 • 4WD • AUTOMATIC
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AC54US
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My heater blower is only working on the HIGH speed setting.
I replaced the resistor with a new one and still only worked on the HIGH speed setting.
I then replaced the AC/Heater control unit in the dash thinking it was the switch, but no such luck still only works on the HIGH speed setting.
Checking the wires connected to the switch I only have power at the BK/TN wire when moving the switch to the different speeds.
Jan 9, 2009 at 5:19 PM
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BLUELIGHTNIN6
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Hello Thanks for the donation. Perform test below on the wiring of switch.


https://www.2carpros.com/forum/automotive_pictures/261618_Noname_100.jpg

Post results and I will follow up. Hope this helps.. Thanks for using 2carpros.com!
Jan 9, 2009 at 7:28 PM
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AC54US
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All checks out good.
One thing I noticed today was when I checked for current at the resistor block I didn't have any.
I went to the blower and unplugged the connector and have current from the green wire to the motor.
Plug the connector back up and don't have any at the DB/YL wire, that leaves the motor to the resistor.. BAD MOTOR ??????????
Thanks,
Gary
Jan 11, 2009 at 2:15 PM
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BLUELIGHTNIN6
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Just to be make certain of the diagnosis, I have a diagram below of the wires you are speaking of. If the one highlighted that says "no power?" is the wire you tested with no power, then yes, it means the blower motor is faulty.


https://www.2carpros.com/forum/automotive_pictures/261618_Noname_118.jpg

Hope this helps.. Thanks for using 2carpros.com!
Jan 11, 2009 at 2:33 PM
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AC54US
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I don't understand why the blower works on high, if it would be bad.
Thanks,
Gary
Jan 11, 2009 at 5:02 PM
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BLUELIGHTNIN6
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Lets back up a bit. In the original post you stated that only the black/tan wire (high setting) has power even after moving switch to other positions. So the light blue, light green, and tan wires all have no power, correct? Just curious, have you tested your relays and fuses located in the power distribution center under hood? The wires come from the switch, to the resistor. From resistor to motor. From motor to ignition, as you probably already know. If 3 of the 4 wires at the switch are not receiving power then problem should lie with the switch, the resistor or a relay. You said you replaced switch and resistor already, so fuses / relays need checked. There are two circuits that power the blower motor. A relay switches between the two different circuits. The high speed circuit suplies battery voltage to the blower. When you set the blower speed switch to any other speed but high the current passes through the other circuit. The blower resistor is in this other circuit. Check the fuse that supplies power to this circuit, check the relay that switches back and forth between the two circuits.


https://www.2carpros.com/forum/automotive_pictures/261618_Noname_120.jpg

Below are labeled components of the PDC. Sorry had to piece it together a bit so the bottom part is bigger than the rest, but it is in correct position.


https://www.2carpros.com/forum/automotive_pictures/261618_Noname2_40.jpg


https://www.2carpros.com/forum/automotive_pictures/261618_Noname3_16.jpg


https://www.2carpros.com/forum/automotive_pictures/261618_Noname4_8.jpg

Post results of inspecting fuses/relays and I will follow up. Thanks for using 2carpros.com!
Jan 11, 2009 at 5:31 PM