2018 Ram 2500 - New blower motor only turns on if I unplug/plug it with vehicle off.

[Aortman]

I recently replaced my blower motor and resistor. My old motor was acting 'tired' and the flow was weak although it was sufficient for most outside temperatures and only struggled to keep up in extreme heat or cold. After replacement, i tested by starting the truck and running the fan controls (8.4in controll with automatic temp included), fan ran great with no issues. I buttoned up my project thinking it was complete.

Next morning, i fire up the truck and head to work, realizing about 5 miles down the road that i have almost zero airflow. There is barely enough coming out to even feel, seems like zero blower and possibly just heat escaping through the vents.

I cannot get it to run again, except for one strange order of operations. If i turn the truck off, unplug the blower motor, turn the truck on and then plug it in again it suddenly works for as long as the truck is on. I've tried all the knobs and electronic button alternatives and it seems that everything works fine. When i turn the truck off, and back on again, no blower fan at all, unless i repeat the specific steps i mentioned.

I've checked the ground wire coming to the resistor as that was a thought and am getting 1.2-1.5 ohms, which should signal that its functioning properly.

I replaced both the fuse, and the relay in the fuse box under the hood. I also pulled the fuse box up and wiggled the connecting wires underneath to see if they would kick on the blower, but no luck there either.


I'm not sure what else to try or if anyone has eperienced this before. Please advise if you have a thought or perhaps have been where i'm at before. Thanks.

Thanks,

Arlis

 

[TJP440]

Sounds like a ground issue. I'm not familiar enough to know if they run the ground or power through the blower switch, may have been the original problem with low air flow, maybe someone else with more knowledge on the circuit will chime in

 

[Aortman]

I updated my original post with more accurate information. I'm really struggling to find anything that i can try to fix to get this blower working properly

 

[1999 White C5 Coupe]

I recently replaced my blower motor and resistor. My old motor was acting 'tired' and the flow was weak although it was sufficient for most outside temperatures and only struggled to keep up in extreme heat or cold. After replacement, i tested by starting the truck and running the fan controls (8.4in controll with automatic temp included), fan ran great with no issues. I buttoned up my project thinking it was complete.

Next morning, i fire up the truck and head to work, realizing about 5 miles down the road that i have almost zero airflow. There is barely enough coming out to even feel, seems like zero blower and possibly just heat escaping through the vents.

I cannot get it to run again, except for one strange order of operations. If i turn the truck off, unplug the blower motor, turn the truck on and then plug it in again it suddenly works for as long as the truck is on. I've tried all the knobs and electronic button alternatives and it seems that everything works fine. When i turn the truck off, and back on again, no blower fan at all, unless i repeat the specific steps i mentioned.

I've checked the ground wire coming to the resistor as that was a thought and am getting 1.2-1.5 ohms, which should signal that its functioning properly.

I replaced both the fuse, and the relay in the fuse box under the hood. I also pulled the fuse box up and wiggled the connecting wires underneath to see if they would kick on the blower, but no luck there either.


I'm not sure what else to try or if anyone has eperienced this before. Please advise if you have a thought or perhaps have been where i'm at before. Thanks.

Thanks,

Arlis

Did you use an OEM Mopar motor assembly?

Since the new motor initially works when it is unplugged, then plugged in again - I would suspect the plug for the motor.

Have you examined it closely? Any bent or corroded contact pins?

 

[Aortman]

Here is the part that i purchased and used. Not mopar specific as far as i know.

 

[Aortman]

Pins and connectors look good, clean and straight.

I’m also hearing an occasional single ding sound. Perhaps truck trying to tell me something is wrong, but no messages or codes to go along with it.

 

[Aortman]

I replaced the resistor with an OEM from Napa and the problem fixed. The single ding continued though and after a few days the blower is right back to not pushing air again. Perhaps the control module or cheap blower motor?

 

[Ken226]

I replaced the resistor with an OEM from Napa

Are you sure it was OEM?

I looked on Napa's website and they list some cheap aftermarket resistors, but I don't see any Mopar OEM resistors available from Napa.

I've used a replacement blower from O'Reilly's in our Durango and it's been running good for over a year now.



If you want OEM Mopar, RockAuto carries them.

The Motor:




The resistor:

 

[EdGs]

Not sure if this can be a 4th gen problem, but on my '02 Ram 1500, I would get airflow at times, then it would go out very intermittently.

I finally removed the blower motor and reached up into the hole. Lo and behold, the door had broken and was laying over above the center of where the blower wheel would be.

It must've been blocking the inlet to the blower wheel at times and not at others. I ended up removing it. The dash on that ram is very crumbly, given it's age.

 

[Aortman]

Napa assured me that it was an OEM replacement.

 

[Aortman]

Part number BR625, resistor out of Taiwan.

 

[Ken226]

Part number BR625, resistor out of Taiwan.

Yea, that's an Echlin brand, aftermarket.

When a parts store says something is an "OEM Replacement", they mean that it is supposed to replace, the OEM part. Not that it IS an OEM part.

The OEM part brand will be "Mopar" and it's part number will look something like, 68048900AA.

That doesn't mean that the resistor is your problem though. It's probably more the aftermarket motor or a blend door than the resistor.

 

[TJP440]

Can you get a voltage reading at the motor connection? That would help a bunch. even if you have to use jumpers to the voltmeter.
Also be aware that you can have a low resistance with a bad connection as it's not carrying any current, but when you put current through it it causes a voltage drop

 

[Aortman]

Is that a resistor or a control module. Looks like the wrong kind of attachment

 

[Ken226]

Is that a resistor or a control module. Looks like the wrong kind of attachment

When I want to see actual pictures of a OEM part, I usually look up a used one on ebay. Ebay sellers tend to have more actual photos. The OEM parts sellers like MoparPartsGiant usually suck for images.

Mopar Blower Motor Resistor Part Number: 6804 8900 AA | eBay

This Mopar Blower Motor Resistor is a high-quality part that will ensure your HVAC system operates smoothly and efficiently. With a part number of 6804 8900 AA, it is easy to identify and purchase the exact component you need. Made by a trusted brand, Mopar, you can be confident in the...

www.ebay.com

 

[Aortman]

I bought a mopar part resistor, that was linked from rock auto in this thread, but for the life of me cannot figure out where it goes. The resistor that I remove is a wide, flat plug with several wires. The one you have above and the one I bought for my vehicle is a 2x2 configuration on the plug. Outside of just buying a mopar blower I have no idea what to try next.

 

[Ken226]

I bought a mopar part resistor, that was linked from rock auto in this thread, but for the life of me cannot figure out where it goes. The resistor that I remove is a wide, flat plug with several wires. The one you have above and the one I bought for my vehicle is a 2x2 configuration on the plug. Outside of just buying a mopar blower I have no idea what to try next.

Got pics?

What was the Mopar part# of the OEM, original, that came out of your truck?

What was the part# on the RockAuto replacement. I looked your part up on several sites and they all show 68048900AA

When I look up a part on RockAuto, all I can do is enter the year, make,model. You'll probably have to be the one to open the box, verify that it's the right part, send it back if not, etc.


When I look up videos, everything I can find shows it to fit into an opening in the HVAC box, behind the blower motor.

 

[Ken226]

I bought a mopar part resistor, that was linked from rock auto in this thread, but for the life of me cannot figure out where it goes. The resistor that I remove is a wide, flat plug with several wires. The one you have above and the one I bought for my vehicle is a 2x2 configuration on the plug. Outside of just buying a mopar blower I have no idea what to try next.

I went and looked in my truck, and it has the resistor that you described. My 2013 1500 has a wide, flat, 4 pin plug like you describe,

I wonder if there were two available for these trucks?

This is the one my 2013 1500 uses.

68018105AA - Mopar Parts Giant

www.moparpartsgiant.com

A used one on ebay.

13-18 RAM 1500 HVAC Blower Resistor OEM | eBay

13-18 RAM 1500 HVAC Blower Resistor OEM. Condition is Used. Shipped with Standard Shipping.

www.ebay.com

Kinda weird, but when I look up that part# 68018105AA on RockAuto, it also shows up as fitting a 2018 Ram 2500. So, i'm not sure why there seem to be two different blower resistors that could have come on these trucks.


More likely, I think, Is that MOPAR got the fitment charts wrong and everyone else just copies off of them. So, everone is wrong.

My guess, the 4x4 plug like you got, fits 2009 thru 2012 and the wide 4 pin plug fits 2013 and up. But, that is just a guess.

Because RockAuto definitely shows both version as fitting a 2018 2500.

 

[js12278]

Here is the part that i purchased and used. Not mopar specific as far as i know.
View attachment 562218

Wrong part
You’ve got 8.4 with auto temp control according to your original post

 

[Jon Schenke]

I recently replaced my blower motor and resistor. My old motor was acting 'tired' and the flow was weak although it was sufficient for most outside temperatures and only struggled to keep up in extreme heat or cold. After replacement, i tested by starting the truck and running the fan controls (8.4in controll with automatic temp included), fan ran great with no issues. I buttoned up my project thinking it was complete.

Next morning, i fire up the truck and head to work, realizing about 5 miles down the road that i have almost zero airflow. There is barely enough coming out to even feel, seems like zero blower and possibly just heat escaping through the vents.

I cannot get it to run again, except for one strange order of operations. If i turn the truck off, unplug the blower motor, turn the truck on and then plug it in again it suddenly works for as long as the truck is on. I've tried all the knobs and electronic button alternatives and it seems that everything works fine. When i turn the truck off, and back on again, no blower fan at all, unless i repeat the specific steps i mentioned.

I've checked the ground wire coming to the resistor as that was a thought and am getting 1.2-1.5 ohms, which should signal that its functioning properly.

I replaced both the fuse, and the relay in the fuse box under the hood. I also pulled the fuse box up and wiggled the connecting wires underneath to see if they would kick on the blower, but no luck there either.


I'm not sure what else to try or if anyone has eperienced this before. Please advise if you have a thought or perhaps have been where i'm at before. Thanks.

Thanks,

Arlis

Did you find the fix to your issue? I have a 2018 2500 Laramie doing the exact same thing.
Thanks

**Update**
I did figure out my problem. It was the blower motor resistor. I replaced the original that failed with a new part from Orielly's. It worked for a few days and quit again. I assumed it was something else. And finally, after checking everything else it came back to the resistor again. I changed it again and now back in business. I highly recommend only using oem parts. I would have avoided a lot of headaches if it did that first.