Just some background...I am running a nelson tune and using his ls1 harness for my ls1 fans.
My e-fans are only running one fan at a time. I switched the female plugs on the harness from the fan that was working to the fan that wasnt and it started working. However, this is my second harness and it did this with the last one (allen sent me another one thinking it was the harness). I am beginning to think that the tune isnt programmed for the ls1 fans. It should be running both fans at once.

 

No, it should not run both fans at once. The one fan comes on with the AC compressor, and the other comes on when the truck needs to cool down a little. Is it overheating? This is the way mine are wired up and I have no problems in the Florida heat.

 

Only one of my fans work at all times. From when my truck turns over to when it is running in 100 degree heat with the A/C compressor running, only one fan works. My truck never overheats, but it is annoying that only one fan (the passanger side fan) only works.

 

Maybe the driver's side fan motor is bad? My fans both come on low when the engine reaches turn on temp, one comes on high with the a/c on and engine not up to temp, and both come on high with engine up to temp and a/c on. Try testing the inoperative fan by running power and ground direct from the battery with jumper wires...if the fan doesn't turn on, the fan motor is probably poop.

 

I double checked both fans and they are both working fine. I am not sure what is wrong. I will get in contact with Allen at Nelson Performance and see what he says I guess. Keep you updated.

 

This is how my Nelson harness is wired up. But I did have a few problems with my harness.....it works fine now

James