does it have and affect to the underdrive pulleys, as in power, or just fix the alternator issue

You'll just have to understand.....that my truck being a lariat had a lot of electric extras on it both stock and some that I added.....I was one to let my truck idle in the winter also....ya I know that's bad.....but increasing the idle hurt the fuel consumption.....so I got myself one of those overdrive puppies and lowered the idle....I do still have one blank one that was going to get the back machined to match the one I gave back but that never happened.....

I hear ya, might be good idea for me i let mine idle in the winter and i have hids in headlights and fogs.