As Dan said, check and make sure you are getting 12V to the fan first (using something structural for grounding the meter). The resistor block controls the ground side.

 

I doubt it's the blower motor. Still betting on the switch.

 

I'm having some sort of electrical problem with the resistor burning out., since June I've replaced it 3 times, replaced the blower motor, and the fuses. And today the 4th resistor burnt out with the harnest. I still can't figure it out.

 

What brand blower motor? Did you replace the harness last time?

 

SHOWSEN PM9200. And yes I did replace the harness the last time.

 

I'm having a similar problem with my 2010 Dakota Bighorn 4.7, my ac works fine for around 45 minutes on high then the blower fan cuts to low, still blows cold but at low speed, if I shut the blower and ac off for awhile then turn it back on it operates as it should, I'm thinking a relay or something is heating up and shutting down. I don't need to turn it off for very long, 5 minutes or so, any help would be greatly appreciated.

 

It was the blower motor y’all. Thanks for all y’alls help!

 

Keep in mind the contacts on the ignition module can wear down an cause it too..Mine was corroded .

 

You saying it can cause the blower motor to basically run itself out?