That's not how it works. For a given voltage, the battery can provide a specific maximum level of current. This is a function of the battery's source impedance (which is typically very low for car batteries). As the battery is discharged, the voltage drops. As the voltage drops, the amount of current the battery can source drops as well. If you keep the truck OFF yet turn several accessories ON while watching the voltage across the battery posts with a multimeter, you will see the battery voltage steadily fall.

I don't think it's fair to say that the alternator is the primary source of power. The battery and the alternator work together. The alternator's job is to keep the system in equilibrium.

Not necessarily. Your issues could have to do with voltage drop between the source and the load. Again, I'm not saying that it's impossible you have a bad alternator. I'm saying your observations do not coincide with one another. In one post, you mention that the blower motor and headlights cannot be on at the same time. But then you go on to say that in this same situation, you are measuring 13 volts. That indicates a healthy charging system to me.

Why are you so reluctant to at least take a look behind the dash? Set the truck up in the problem state and pull out your multimeter. You do have one, correct? Measure the voltage at the accessory causing an issue, then measure the voltage across the battery terminals. If they are low and equal, then I'd believe there is a charging system issue. If the battery is at a healthy voltage (like you saw at the parts store) and the voltage at the accessory is low, then there is something going on in between.

You're essentially presenting a vehicle with heavy electrical modifications, and blaming your issues on the charging system using data that does not add up. You've either got to prove your electrical modifications are not an issue OR figure out why your data with respect to the charging system does not make sense. It's up to you if your path for solving the latter is simply replacing the alternator. If that solves the problem, then that's great news. I'm simply saying that if this were my truck and I was the one spending the money, I would not have enough of a "warm and fuzzy" that replacing the alternator would solve the issue because it doesn't make sense to me why yet. I personally refuse to draw any conclusions about my truck's electrical system without the use of a multimeter and I don't get the sense that you've actually pulled yours out yet.

 

Think of the battery as a bucket full of water (electrical potential), a spigot at the bottom of the bucket which provides the output flow (the load), and the alternator as the pump which attempts to keep the bucket full of water.

 

I have checked all the systems for what they are pulling using my multimeter. All systems read ok....meaning no above average draws. My dad is also a mechanic and I also had him check it and he said he found nothing as well.

 

That's not what I suggested you do in my previous post.

 

Did you try what fmc400 and I suggested? Take a voltage reading at the battery terminals then at your fuse block inside the cab and see if you have any voltage drop. How were they checking the amps the alternator was putting out? The way I read it seems like your truck defies OHM's Law....

 

The first place I would look is the factory Fuse-able Links that are between the battery and the fuse panel, should be around a maximum of 12" from your solenoid. In my experience that seems to be the first weak link. Then your voltage regulator that is a decades old piece of what was already antiquated electrical technology.

And after those simple, quick tests then go down to the junkyard and pull your desied alternator. Even though like others I am in doubt that your alternator is the "only" problem in your Electrical (not just "charging") System then even putting in a good factory OE alternator would deal with it.

Too small a battery, weak alternator, voltage drop/ground issues= problems.

How much is your stereo drawing, do you have an Amp or multiple? You mentioned a backup camera, does that mean you have a flip out DVD head unit or another added accessory screen. My point is I don't think you are factoring in all the draw you're demanding from an already insufficient system.

FINALY when "exactly" did these problems begin? "Like that when I bought it", after something was changed or added, driving Ms Daisy and $#!T went haywire?