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Heater Climate Control Unit fan switch failure?


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It seems as though my fan switch has become a happy face Sad face type of fan switch.  It works on high only.  I suspect the switch may have failed.

 

I do have AC I do not have heated mirrors.  I believe the unit is P/N 55056702AD

 

If anyone has any other thoughts on why that would be awesome.

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Blower motor resistor(s) need replacement. Also, if the blower motor is drawing enough current to cook the resistors, you likely need a new blower motor as well, or you'll be replacing resistors again.

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I would verify the part number, but absolutely. If you aren't doing the blower motor as well, I'd at least recommend using a clamp on ammeter to check the draw of the current draw. However I don't know what the desired specs of the motor are to compare. 

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23 minutes ago, kzimmer said:

Blower motor resistor(s) need replacement. Also, if the blower motor is drawing enough current to cook the resistors, you likely need a new blower motor as well, or you'll be replacing resistors again.

And this:

https://www.amazon.com/gp/product/B079JG2NTH/ref=ox_sc_act_title_1?smid=A26XZY1DGLFZZH&psc=1

3 minutes ago, kzimmer said:

I would verify the part number, but absolutely. If you aren't doing the blower motor as well, I'd at least recommend using a clamp on ammeter to check the draw of the current draw. However I don't know what the desired specs of the motor are to compare. 

Yea if I'm going to have party under my dash I may as well replace both parts while I'm fooling around under there.

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Just now, kzimmer said:

Makes sense to me. I haven't done either of those parts on a 2nd gen Dodge so I'm not sure how involved it is. Shouldn't be too bad. 

I already found a couple of videos on Youtube.  It looks super simple for both.

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Posted (edited)
4 minutes ago, pepsi71ocean said:

Its fairly simple on these trucks. And most likely the resister switch is going out. The actual switch had a almost noon existent fail rate.

Not sure where the resister switch is.  Can you throw me a bone?

 

Do you mean this guy?

https://www.amazon.com/gp/product/B07K2WPD2C/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Edited by leety
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When you remove the blower motor you will see it on the left side or rear in the hvac box. Its pretty obvious once you are contorted under there. The part you linked looks right. I did not compare any part numbers though.

Edited by dripley
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When you replace the blower motor because the bearings are bad. Then right next to the blower is a another plug. This little unit is the blower resistor and is held in with 2 Phillips screws. The only reason why the blower resistor failed is because the bearing on the motor dried out and stiffened up, this causes rises in amps drawing through the resistor and getting too hot it shatters in the HVAC box. Always replace as a pair.

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I changed both too, then later put some oil on blower bearings and it spins fine again, I put it in the box and on the shelf for spear parts. Not sure how long genuine chinese one is going to last. I try not to discard any old pats anymore unless they are unrepairable as most new is a 50/50

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7 hours ago, Dieselfuture said:

I changed both too, then later put some oil on blower bearings and it spins fine again, I put it in the box and on the shelf for spear parts. Not sure how long genuine chinese one is going to last. I try not to discard any old pats anymore unless they are unrepairable as most new is a 50/50

 

I bought my replacement fan from the dealership.  It even included the fan plug as well. My new one works great.

 

Now for the rest of my truck ........

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Ok new weird phenomenon.  I installed the new resistors and tested them and all was well.

 

Then I replaced the fan/motor and it spins but no air is coming out of the vents.  

 

Any ideas/suggestions would be welcome!

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Do you have air flow through the defrost or floor vents? 

If no, then the fan motor is running backwards.

 

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1 hour ago, Mopar1973Man said:

Yup, you need your vacuum pump on the engine twist to make vacuum to pull the doors open and closed. Yup, defaults to defroster... 

Okay so rookie lesson learned.  Now I know, no engine running, no vacuum pump pumping, no door heater/HVAC actuation.  Derp.

 

Thanks everyone.

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