ok i searched the forum and came up with nothing telling me exactly how to do this swap, so how do I do it, what is needed, and what is the final cost going to be? Would it be more cost effective to just buy a new 100 amp alternator from LMC? I'm powering at most my headlights, my upgraded stereo with 2 speakers, my fog lights, and maybe my AC/heat. I currently have a 55 or 60 amp alternator that came stock on my truck and it can barely seem to fun my radio and my bright headlights at the same time.

 

How hard did you search? There are literally dozens of threads about it. Here's a more recent one, which also links to some other ones:

https://www.ford-trucks.com/forums/9...g-upgrade.html

It would not be more cost effective to get a new alternator from LMC. You would also lose the advantage of an internally-regulated alternator.

A 55-amp alternator is plenty to power your radio and headlights. If you're seeing anything different, then something is wrong. A lot of people are going to tell you to "screw it" and go ahead and upgrade to a 3G alternator in hopes this will solve the problem, but that's not a guarantee. You could have a pre-existing issue upstream of the alternator. Diagnose the problem first and then decide if you want to upgrade. Don't build a house on mud.

What are the actual symptoms? You've mentioned there is a problem, and what you suspect to be the cause - but neither are actual symptoms that can facilitate a troubleshooting discussion.

 

I tried searching "3g alternator swap" and got no results that were relevant in my case. i know that many many people have done it, so I figured someone could just point me in the right direction.

Anyway, my symptoms are this: When my truck is running/driving, and I turn on my fog lights (aftermarket), my radio shuts off. When I turn off my fog lights, my radio instantly comes back on as well as the screen for my back up camera. When I am driving and I have on my headlights and radio, if I flip on the high beams the radio goes dead. Flip on the low beams and it comes back to life. Same thing goes for turning on AC or blower motor in general. I cannot run the headlights and blower motor together because if I do, my headlights are very dim and almost useless. My battery was new as of last year and is a 550 CCA battery from Walmart. The alternator is original. It sounds to me as if the alternator cannot handle the current load pulled by any accessories, because the accessories work fine when used individually, but not if I'm using two or more at a time.

 

i would check all your grounds really good. Not saying the alternator is not weak but sounds like you also have some underlying issues. Time to get the multimeter out and do some checking. I would start and see if you have a voltage drop from what you read on the battery post and whats in the cab at the fuse block and other areas

 

With over 180 posts, ya should already be familiar with the hyperlink compilation sticky at the top of the forum page. Try it sometime.

Final cost? Some have done it complete for as low as $20, but I figure most around $50. Something's gonna be wrong if it costs ya more than $75.

 

The issues you're describing are due to a problem, not because of deficiencies with the stock charging system. Ford wouldn't have been able to sell a vehicle that couldn't have the radio on at the same time as the lights.

A lot of the issues you're describing don't even sound related to the charging system in the first place. Things shutting completely off with others on could be a short in the dash wiring. If that's the case, the problem would still exist in the presence of an upgraded alternator. That's why you need to solve your current problems before upgrading the alternator. Get back there and start checking (especially since it sounds like some accessories have been added).

 

are your foglights running through a relay? if not, they should be.
go back and visit how all of your accessories are wired in and you will probably find the problem.

 

Just had my charging/electrical system checked and it turns out I definitely need an alternator. My alternator is currently pumping out less than even the minimal level that it should be pumping out. There is nothing wrong with the wiring at all.

 

how many volts was it putting out? the battery alone will be able to support those things running together

 

14 volts unloaded, 13 loaded. AMPS were the issue. The battery checked out in perfect shape according to the tests. The system mainly relies on power from the alternator for power. However in this case, since the alternator barely works, the systems are relying more on the battery than it should. According to this test, the alternator is pumping out 2 amps unloaded, and 5 amps loaded...kinda sounds like that's the issue...

 

Something's not adding up. The charging system cannot maintain a regulated voltage unless the alternator produces current. If you don't have current, you won't see the voltage stay up. To that end, the alternator only outputs enough current to meet demand (where "demand" is defined as the current necessary to maintain 13 to 14 volts across the battery terminals despite loads that demand current from the battery).

If your electrical system is in such bad of shape that turning on the headlights shuts off the radio, there is no way you're maintaining 13 volts. What are you calling "loaded" and "unloaded?" No one's stopping you from going ahead and replacing the alternator - if that fixes the issue, then more power to you. All I'm saying is I don't completely understand the observations you have listed based on your description alone.

And Fordboy88 is correct. Even if the alternator was completely removed, the battery by itself should be able to keep all of these accessories on at the same time (of course the voltage would fall gradually). Again, things are not adding up. I don't see how you can immediately claim that there is nothing wrong with the wiring of all your accessories without taking a look. Seems like everyone in this thread is saying the same thing (except for you).

 

Loaded: blower motor on and bright lights on.

Unloaded: all but the engine is off.

The battery can power the accessories and still maintain voltage. However, it will substantially and quickly drop amps because that is what the accessories are pulling. The alternator to the best of my understanding, the alternator is the primary power source that yea, when removed shouldn't cause a problem. But my battery is also very small. It is 550 CCA. It should at least be 650 CCA.

This may be my backwards thinking here, but if my accessories had a problem, wouldn't I be blowing fuses?

 

Also, if all my accessories work fine by themselves and work for a short time when more than one accessory is on, that tells me that nothing is wrong with them. According to the test results im looking at, I see that the alternator is not meeting the demands of even two accessories. Yes, the alternator should kick in when its needed and increase its output as the demand for amperage increases, but mine does not. It puts out just enough voltage to keep the battery charged, but the battery is what is powering my accessories, which is why if I turn on too many at once I run out of power.

 

Fuses blow when there is a run-away current.. like a short to ground. The over-current literally melts the lil metal bridge in the fuse because of excess heat caused by drawing excessive current.

I concur with fmc400's evaluation.

 

I did as FMC said earlier, did the 3G expecting it to solve my issues. It did,,,, for a while. Now I'm learning about my electrical system the hard way. My stereo crapped the bed this morning. All I had time for today was to check the fuse. Tested good. Good for voltage as well. But that's my issue.
So in fact the 3G upgrade gave me about three months of worry free driving. Now I have to actually troubleshoot my electrical issues.
That's just what I have learned. Still and yet I'm glad I did the upgrade. Just wish I would have done it right the first time. Because now I will have to do it all over again. Believe you me, I will be doing it right this time.