I have a 2002 1500HD and I just put a set of 05 E-fans on with a nelson tune and harness. My question is this, when my AC is on the clutch cycles on off about every 8 seconds (I timed it). The way nelsons harness is the pass side fan cycles on off at high speed every 8 seconds. This doesn't seem right or very good for fan reliability in the long run. I did have the dealer check my ac system out and everything is perfect. Here is my thought why not have the pass side fan come on low and stay on low when ever the ac is turned on with the switch on the dash. I would think the computer could do this, could it? What do you guys think? The 8 second cycling is driving me nuts!! How do these fans work on a 05 truck with the ac?

JK

 

Depending on the ambient temperature, the a/c compressor will cycle more or less...on a hotter day it will run more and cycle less, on a cooler day it will cycle more (on/off). You want the fan running when the compressor is running to cool the condenser and allow the a/c to operate at it's maximum ability. Every vehicle that I've ever worked on w/ electric cooling fans has operated this way.

 

This is the way it works. Perfectly normal. The fan is actually spliced into the compressor clutch circuit - which is why it cycles with the clutch.

This will happen when just running the defroster as well.

 

that is the way mine is. that is right. i have been thinking about hooking to the switch for that a/c trigger. i think that it is a ground. so i would just have to rearrange the fan wiring. sitting in traffic this i believe that it will help out more. hmm. i need to ask allen about making it run at 50% while the switch is on.

 

I understand that the fans are working properly for the setup that I have, but I would like to know if that can be changed to run on slow when the ac switch is turned on. I think 02denali knows what I am saying. I would think that could be something done through the computer maybe?

JK

 

The actual A/C signal request circuit is only 8.8 volts and will not trigger the relay. Wanted to do that myself and quickly found out that I could not. That circuit makes the most sense to use, but it doesn't seem to be an option.

 

Can't do anything through the Tune to my knowledge. You would have to modify the wiring harness.