I have searched for an answer, but can't find one so I'll ask it here.
Have 05 e-fans, nelson harness, on our Tahoe.
When engine gets to set temp, fans come on low.
When Ac is on fans work low,
When Ac is on and engine gets to temp both fans come on High.
But fans don't come on high when temp is met on high temp setting.
Only 1 wire going to PCM ( pin 42 )
Is there a way to get fans to run on high speed when engine gets to set tempture?
I don't care if I don't have low fan speed, would just like to have high speed
when engine gets to temp, without Ac being on. Using PCM only. Not a manual switch.
Any help appreaciated

 

With the three relay harness the fans are only going to run on high with the A/C on and the temp met. You can make them come on high with the two relay harness but then one comes on with the A/C, one with the temp, and both with the temp and A/C

 

You could buy a socond fan controler with another temp sensor......