WWDiesel wrote:
This system has never made a lot of sense to me. If you pull either one of the relays, high or low speed, the ECM will energize the single relay still in place and the fan will run. Not sure why this is as the wiring diagrams does not provide any answers.
Just a wild guess!
Without testing on my own, it may require both relays energized at the same time to get high speed and either one of the relays singularity to get low speed?
Interesting...if the fan is rated for 24v and if the relays to the fan are wired in SERIES, but then again how would that make sense since the Jeep has only ONE 12v battery powering BOTH relays.
Or perhaps the fan motor has TWO windings and each relay energizes one of them. I think that this is more likely!
I will disconnect the fan and try energizing the relays individually and combined while checking the voltage at the fan connector...
Still, this is a little hard for me to wrap my brain around,,,MAYBE that is why there is a 3 pin connector for this fan?
I know you said that the fan wiring diagram doesn't show anything decisively, but do you have a link to the wiring diagram??
TIA