How to Replace Blower Motor Resistor 1999-2007 Ford F250 Super Duty Truck
Created on: 2011-11-17
Watch this video to learn how to replace the blower motor resistor in a 99-07 Ford F250 Super Duty truck.
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step 1 :Diagnosing the Problem
- Turn your vehicle on
- Try to run the air conditioning at all its different speeds
- If the fan speed doesn’t change at each setting, the blower motor resistor is not working
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step 2 :Removing the Blower Motor Resistor
- Remove the two 8mm bolts from the resistor
- Pull out the resistor by hand
- Disconnect the resistor wiring harness
- If the harness will not separate normally, use needle nose pliers to break parts off the plastic resistor housing
- Use a flat blade screwdriver to pry the resistor away from the plastic housing
- Use the screwdriver to pry the resistor housing off of the wiring harness
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step 3 :nstalling the New Blower Motor Resistor
- Apply Penetrating oil to the resistor wiring harness
- Put the new resistor into place
- Start the upper bolt by hand
- Start the lower bolt by hand
- Tighten the 8mm bolts
- Connect the wiring harness
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step 4 :Testing the Blower Motor Resistor
- Step 4: Testing the Blower Motor Resistor [6:40]
- Turn your vehicle on
- Try to run the air conditioning at all its different speeds
- The fan speed should be different at each setting
- If it is still not working, disconnect the wiring harness, apply grease and more penetrating oil, and reconnect the wiring harness
- Retest the blower motor
Tools needed
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Socket Extensions
Flat Blade Screwdriver
Phillips Head Screwdriver
Rust Penetrant
8mm Socket
Anti-Seize Grease
Ratchet
Needle nose pliers
Brought to you by 1AAuto.com, your source for quality replacement parts and the best service on the internet. In this video, I'm going to show you how to replace the AC and heater fan speed resistor on this 2003 F-250, same as any '99 to '07 F-250 and F-350. In a perfect world the only tool you'll need is the is the 8 millimeter socket with a ratchet and a small extension but most of these go bad because the contacts corrode so you'll need some needle nose pliers as well as a flat blade screwdriver to force the resistor and the harness plug apart. Then some penetrating oil and grease to condition the contacts before you put it back together.
With they key on, turn on the ... Now if you listen you can hear the blower motor and as I turn it up you don't really hear any difference in the sound of the motor. Then when I go to high ... okay, so I'm basically missing my 2 middle speeds and this is not the switch, it's usually the resistor. Blower motor resistor is right here on the passenger side. This is it right here and it's held in by 2 8 millimeter screws, one up there and then there's one down below that you can't really see. For the bottom one, I've got an 8 millimeter socket. If you have a small extension like that it'll help but you can just do it with a socket and ratchet. Okay, I'm just going to hit fast-forward here so you don't have to sit there and watch my hands working a ratchet.
Now once the bolt's not giving the ratchet much resistance then you can just reach in there and take it out the rest of the way with your hand. Again, fast-forward for that top bolt. Use the ratchet and then once it doesn't give resistance, use your hand. You might ask why didn't I unplug it first, because generally these things are so corroded together that they don't just unplug in the conventional manner. What I usually do is take a pair of needle nose pliers ... You don't want to break the harness part of the connection but ... I just start breaking the resistor side. I'm going to fast-forward here as I go at the plastic part of the resistor side. Again, do not break the part of the plug that the wires go into. You want to just break off the plastic that is part of the resistor. You can look at your new resistor to see which part that is. Now I'll trade in for a screwdriver and now I'm just trying to pry away the remains of the resistor from the connection.
Once you get it pretty much to that point ... This doesn't want to come apart ... Now you've gotten the resistor part off ... now the plastic part ... Put your screwdriver in there, pry up ... I generally like to take a little penetrating oil and clean up the contacts a little bit. New resistor from 1A Auto, only the color is a little different. Put it back in place. Start our upper bolt a little bit by hand first. If I reach in here with my left hand underneath, I can feel the hole and start our lower bolt as well. Make sure it's in there well. Now I'll just use my 8 millimeter socket with my ratchet and extension and tighten up those 2 screws. When you tighten them up, you want to tighten them firm but don't over-tighten them because you could strip the plastic housing. Okay, that's installed. Now we can take our lead and plug it back in.
At this point you're going to want to run a test, see if you have all your speeds back. I found on this truck that I actually ... it changed and that was because the contacts still weren't making good contact so I actually unplugged it again, sprayed some more penetrating oil in there, then re-plugged it in and just moved the connection around a little bit and that restored my fan speeds. Also, putting a little bit of bearing grease or something more permanent on there, that helps make a better connection with the prongs clips. Now you can hear speed 1, 2 ...
We hope this helps you out. Brought to you by www.1AAuto.com, your source for quality replacement parts and the best service on the internet. Please feel free to call us toll free 888-844-3393. We're the company that's here for you on the internet and in person.
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