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Mopar Certified
Mopar Certified, Dodge Technician
Category: Dodge
Satisfied Customers: 11332
Experience:  24 Year Chrysler/Dodge Certified Specialist
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2005 Dodge Ram 3500: blower motor resistor..its own with a 12v jumper

Customer Question

My 2005 Dodge Ram 3500 climate control system stopped working. I replaced the blower motor resistor and it still does not work. I tested the blower motor and it runs on its own with a 12v jumper. I cannot find any relays only fuses for the system. What is my systems problem and how can it be fixed?
Submitted: 8 years ago.
Category: Dodge
Expert:  Mopar Certified replied 8 years ago.

So, this is just a problem with the blower motor, then?


Do you have a volt meter to check for voltage on the dark blue wire at the motor?

Customer: replied 8 years ago.
when the truck is driven down the road hot air comes into the cabin via the defroster. I checked the voltage at the motor without it connected and get 10.7 volts to solid blue wire. none to blue with yellow stripe.
Expert:  Mopar Certified replied 8 years ago.
You should be getting battery voltage to the blue wire with the key on. Unless your battery is currently reading 10.7 volts, you should have about 12.6 on that wire. This could indicate high resistance in the circuit due to a burned connection at the ignition switch. Remove the covers from the top of the column and check the voltage coming out of the switch......paying close attention for any signs of an overheated terminal.
Customer: replied 8 years ago.
on which wire?
Expert:  Mopar Certified replied 8 years ago.
You're still checking the blue wire......just at the ignition switch this time..........the wire goes from the ignition switch to the blower motor.
Customer: replied 8 years ago.
at the ignition switch its 14.1 volts. at the motor with truck running and selector on high 13.3 volts off position 12.9. truck off but it in on position the voltage is as 10.7. may be dropping due to glow plugs and other draw on system.
Expert:  Mopar Certified replied 8 years ago.

OK, so the motor is getting power, so you are missing the ground.


If the motor is failing to run, even in the high position, then the heater control head is likely at fault.


You can remove the heater control panel and verify that it is properly grounded on the black/light green wire. If you have a good ground here and the motor won't run on high then the panel is faulty.

Customer: replied 8 years ago.
ok i tested from black green wire to known hot ( cigarett lighter plug) and got 14.1 does this indicate good ground? also i noticed none of the wires on that plug group had any hot voltage. is this normal? i was only able to find hot on a low voltage wire in the second plug when running lights on.
Expert:  Mopar Certified replied 8 years ago.

Yes, that does prove a good ground.


The black connector should have a grey/pink wire with battery voltage on it in the run position.

Mopar Certified and 5 other Dodge Specialists are ready to help you
Customer: replied 8 years ago.
Yes that is in the small wire bundle on the right side. What i was referring to was the large wire connector. The ble wires with the yellow blue orange purple stripes. Should any of those have voltage on them? Or are all of them ground wires?
Customer: replied 8 years ago.
If that is normal then I will need to replace the control head, correct?
Expert:  Mopar Certified replied 8 years ago.

Those are all ground wires for the different fan speeds.


You can ground each of those wires to the black with light/green wire you tested earlier and this will provide a ground for each of the fan speeds........essentially bypassing the control head. If all works, then the control head is faulty.



Customer: replied 8 years ago.
ok guess your done with me now.
Expert:  Mopar Certified replied 8 years ago.
Did you get it sorted out?