cooling fans Cooling fans not coming on

[Louis2015]

My 2015 Silverado has 428,000 miles and I've been having intermediate problems with the fans for the past year.  I recently changed the entire unit (both fans and the plastic housing) and I don't think that did anything at all.  I hate computers.  The drivers side fan coming on slow/medium and the passenger side fun doesn't come on at all.  This causes my 6L80 to overheat and my A/C to blow warm.  I'm on my 3rd 6L80 and I'd prefer to take this one to the million mile mark with the truck.  Does anybody know how to nip this fan problem in the butt!  

[64BAwagon]

I dont have any experience with this exact year of truck but I have had similar issues with GM vehicles. The first thing you need to do is determine if the fan is even being commanded ON. There should be a resistor in the front near the radiator that controls the fan speed. You will need to find the connector and then run the truck and see if theres power being sent to the resistor to turn the fans on. If the resistor is bad it wont supply power to the fans in the stages that the ECM wants. 

The other thing to check is if the coolant temp sensor is functioning properly. If the ECM cannot get an accurate reading then it wont command the fans correctly. 

The last resistor issue I had was on a Cruze. The ECM would signal a low, medium and high fan speed. Since the resistor failed the only thing that actually worked was the high function (which is straight 12v to the fan, not the reduced voltage for low and medium), the ECM commands the high when the temp rises even after commanding the low and then the medium and not seeing a stabilization or drop in coolant temp.