So, I have a 2013 2500 Tradesman, diesel, in case that does matter for this…. The issue I am having is one of occasional loss of blower. I checked the wiring and plugs under the dash, and thank God, nothing was discolored or burnt looking (past trauma with a Durango…), and the motor turns freely and there was nothing jammed in the fan. I did some looking around and some have had an issue where the relay socket in the fuse box gets loose, however it seems like all of the plugs are still tight in there, as its leaving nice deep scrapes on both sides of all the spades on the relay cube itself. And I even tried swapping the spare relay in. I checked the voltage at the motor connector, and with the **** turned to full speed it would get about 8 volts when not working, and that remained the same as i turned it down one speed at a time. Eventually the fan comes back on and when its operating on HI, it gets the full 13v from the battery. I have absolutely no idea where to start with this, is happening, and short of just changing the resistor, I have no clue where to begin. Past experience with another truck was a complete wiring problem behind the dash…

I’m really hoping the people of the forum know more about the HVAC system in these trucks than they did with the EGR… 😫

 

While I'm not a expert in HVAC issue I can tell you thet intermittent electrical issue can be a pain to trace down. That being said, I'd say you need to start narrowing down the voltage loss.....which you are totally aware of. I'd trace the power supply to the fan and start checking the voltage as you go....when it's not operating properly. You might find a loose connection on either side (positive or negative) and just need to clean/tighten a connection. As for the relay, if the pins are loose that could indicate a problem on the input side of those connectors so I'd look there first probably.

 

The blower motor resistor is also pretty easy to test with a multimeter, and typically pretty easy to access. I do not have first-hand experience with where it's located on the 2013 Ram though.

-Rod

 

the blower motor resistor is less than $20 an any auto parts store. Location is super easy to get to. Open the passenger door and stick your head into the foot-well, it's right there where the connector hooks up to the blower. Two screws and it come right off.