Huh? What?

 

At idle, my head lights will flicker a little and I can watch the cab lights do it as well. Also, it does the same crusing down the road and while this is happening you could watch my voltage gauge go from 14 up to 16 or so then drop back down to 8. Since I had it retuned I haven't noticed it doing it anymore.

 

Considering what you've already tried Chris (alternator,belt), this would be my next guess...does your truck have a wire that goes from the alt to the PCM? Maybe something in the tune is telling the voltage regulator to shut down?

 

I think I just put two and two together....I never had this problem before the blower, but I can't see how the blower would cause it. The one thing that did happen though is since I was waiting so long for the blower to show up, my battery voltage at one point got down to about 7 volts. I think you guys might be right, the battery might be bad. I have checked all the wiring, replaced the alternator, and put on a tighter belt. I have an Optima Yellowtop, should be deep cycle but maybe being really low for a couple weeks killed it. I noticed that my alternator "smells" hot after driving for awhile, and with the headlights on and e-fans running on high at idle the voltage will drop to 12.5 or 12.6. I bet the battery is bad from sitting for so long and the alt is really struggling to keep up and gets really hot. Going to have it load tested tonight. Will let you know.

 

Had the battery load tested in the truck today, he said it's barely in the good range. Told me to pull it out of the truck, charge it fully tonight and bring it to him tomorrow so he can do a full test on it, and will likely be replacing it. Hope this works!

 

New battery did not solve the problem either. I wonder if I forgot to hook up a ground when I swapped engine harnesses?

 

DId you put a bigger crank pulley on when you installed the blower? Just an idea, maybe your over charging the alternator and it is heating up causing it not to preform like it should? When you first start it up does it charge fine, then after awhile it get progressively worse?

 

Seems to do it no matter what...I shift at 5600 RPM. I know people that run their factory alternator up to 7000 RPM with a stock crank pulley with no problems, I can't imagine 5600 RPM with an overdrive spins the alternator any faster than 7000 with a stock pulley. I also get voltage drop at idle (12.6) with the headlights on and e-fans on high with a/c blasting.

 

True, i spun my last alternator up to 7k frequently... But my problems seemed to fixed. I was having the same issues and I fixed them by replacing the battery and alternator, I am doing the big three mod this weekend. I will say this tho, those 05+ efans draw some serious power...

 

Yea, my voltage system takes quite a hit when my 05 efans kick on high and the ac compressor comes on, it's even worse after my PCM was tuned to help it, now it seems like the idle settings are messed up and the engine almost stalls when the ac compressor kicks on. I'm sure that when I send my pcm to Justin at BlackBear he'll be able to at least get the idle settings back the way they belong.

I'm curious to see if swapping out the battery fixes your problem...when are you swapping a new battery in?