I thought I was on to something but the relay that I was testing is the low speed relay. That is the relay that puts power out on the third unconnected wire.

 

Did the fans get changed for the wrong ones??

 

Not since I’ve had it. I’ve had this truck for 4 years and this just happened. Everything was ok and working.

 

Someone came along and stole a wire???

I have no explanation for that...... I also don't know if the two speed fan was an optional type thing, or if they all had it. If they all did, I would think that all three wires oughta be there. Might try calling the dealer, and asking about that..... there also might be a TSB about it.

 

I have a 2012 ram 1500 with a 4.7.
I have the same problem with my condenser fan.The high speed relay is attached to the horn mount on the upper rad support.
Pcm tells fan to come on and I believe the Tipm then sends a 5 volt signal to that relay which closes the relay and allows 12 volts to the fan.I still can't get mine to work.There are also micro relays inside the Tipm on the circuit board..