Well i wanted to keep the vehicle close to factory as possible and everything was bolt right on including the factory harness which is actually the foward lamp harness on a 2005 escalade, ext , esv which cost me 140.00 which work out nice i will upload some pic maybe if i get a chance but the nelson harness works the same and cheaper which if im not mistaken is 89.00 plus S&H

 

So it does look like it will work on 03 and 04 trucks also. That is good.

The reason I used the Nelson harness was I couldn't find a salvage harness and a new one was about twice as much and I wasn't sure I could adapt it at the time. A year ago I couldn't get a salvage yard to separate it from the main harness but that may have changed as more of them become available. Others have done it now and the factory harness will work but still is more expensive unless you can get one at a salvage yard. The perfect setup would be a factory harness for cheap.

That is good info on the alternator charging module. That has to help some with the voltage drop. I wonder if it would retro fit the 03-04?

Good it was mentioned about the fan airflow tables needing updating as that has not been said. I used the 05 settings and they seem to work fine.

 

Not sure what year that started, but I think it may be as early as 03? that they started to duty cycle the alternator...I can't remember where I found this info, but I remember that I figured it out when I did my 02 PCM swap and 03 145amp alt install.

To answer the original question of the thread, I see the voltage guage drop when the fans come on high, when the ac compressor engages. It's most noticeable when using the defroster, since the compressor cycles on and off more continuously. I don't even notice when the fans come on low.