Since I installed the efans, I tried to use my heater the other day and I noticed I was getting some big voltage drops like every 10-15 seconds at idle. I was like WTF. I pop the hood and I see my A/C compressor cycling? It does it with ANY fan setting. My truck has the auto-recirculate so that light always pops up unless it's set to defrost. And there too the A/C compressor pops on. So, this is going to destroy my alternator in no time with the fans popping on high every 10 seconds.

1)Is this normal?
2)I'm thinking of disconnecting the A/C trigger wire on my Efan harness to avoid the fans popping on. With these sub 50 degree temps my engine isn't even getting hot enough to turn the fans on low, let alone high. Justin also informed me that the 1 pin harness can fairly easily be converted to the 2 pin harness to use pin 33 in the PCM to control 99-02 trucks via A/C pressures. I'm also thinking of turning this auto recirculation off in the tune (has to be done to run the 2 pin harness).

 

It doesn't sound right to me, almost sounds like the control unit is shorted, but as I mentioned in our PM's, I'm not familiar with the auto-recirc so I'm not 100% sure...

 

It's normal I believe. I have heard that the A/C compressor is still used to help dry out the air. Could be completely wrong, but I do remember hearing that.

 

Yeah, that's what Justin said.

I still prefer the old school cars that had the manual controls for everything

 

Did you have the HVAC set to the defroster? Your defroster/defogger runs off the AC compressor believe it or not, that is perfectly normal for it to cycle......

 

I turned off "auto recirculate" in the tune. Now the A/C compressor doesn't come on.

I've looked at an 03 LQ9 tune and it isn't set to auto recirculate from the factory. It appears that only the 2000-2002 trucks had it.

 

That's an interesting option, glad you got it figured out, you don't need your e-fans kicking on and off every 10-15 seconds when you're running your heater

 

So you had to turn off auto recirculate in order for your 2 pin harness to work?

 

Mine never does this unless I have the controls set over to defroster. It also doesn't recirculate unless I press the recirculate button.

 

If the compressor is coming on without being commanded on there is a problem. Most common is a short in the AC control head. Recirc or fresh air does not matter. AC on or Defrost are the only setting the compressor should cycle. Also if you have installed aftermarket fans be sure at least one comes on when the AC is on.