H3 Alternator R&R from the top. Lots of pictures.
 

Ok guys my alt was on it way out and I didnt want to remove the driver side wheel, inner fender well, AND remove the A/C compressor. So after looking at it I was pretty sure I could get it out from the top. Here is what I did.

Step 1 Put dirty H3 in the garage.
Attachment 16432

Step 2 Ask yourself why GM did this.
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Step 3 Pull battery corver and vent hose.
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Step 4 Remove tie down nut and battery.
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Step 5 Remove wiring harness clips. I think there are 2 of them. They look like this.
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Step 6 Remove the front bracket from the motor. There are 3 bolts on the front and one on the back. DONT NOT BEND THE A/C LINE!!!!
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Back bolt.
Attachment 16439

Step 7 Remove bleeder cap and bleed the fuel line. I put a rag under the valve to catch the gas.
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Step 8 Disconnect the fuel line. It used a 3/8 quick disconnect. Once its off you can use the oil dip stick to hold the line out of the way.
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Step 9 From here I took off the belt and unbolted the alt to see what else needed to go. I didnt take picture of me unbolting the alt. There are 2 bolts on top and one on the bottom. Also make sure you take the main wire off and also unplug the cilp before you try to pull it out. As you can see the rest of the fuse box is in the way.
Attachment 16443

Step 10 Disconnect the harness. Also unbolt the 2 nuts holding the 2 wires on the back left side of the box.
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Step 11 Remove the fuse box. There are 2 cilps on each side. Pull them together and the box comes off.
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Step 12 Remove the main harness plugs from the fuse box base. There are 3 clips that hold them down. 2 of them are in the right said and 1 one the left. You need to use and small flat head on the left clip. The right 2 can be done by hand. Sorry I didnt get a good picture on them.
Attachment 16446

Step 13 Remove the fuse box base. There are 3 bolts that hold it down. You can see the 2 small clips in the bottom of the picture that hold the main plugs in place.
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Step 14 Remove alt. You will have to twist it to get it to come out.
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Step 15 Smile because you just saved yourself alot of time.
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I hope this will help some of you in the future. I will be picking up the new alt in the morning. I will post of some pictures of the install. It sure beats doing it the way everyone says to. It only took alittle over an hour to get this done. Also I dont have any type of repair manual for the Hummer. This was all done on a "well lets see if this works" attitude. The only special tools you need are the fuel line tools.

A true hummer hero!!!bravo,,,takes me back to a similar wiggle struggle with the probe.

It takes brains and imagination and ability to ignore the factory instructions!!!

Grate news!!

0331Marine, great "TECH" post here! Glad to see I won't have to remove the A/C compressor on mine when it is out of warranty and the alternator goes out! Looks like you had some Bees living inside your battery box.

What's that small block in the garage for???

NOW YOU CAN SEE, do u think u could unbolt the compressor but not the lines and move it enuf to avoid some of the fuse work? it looks like the tubing is in the way but how much would it need to move?,also the heavy elect cable?

its raining or id go out and peek!!,i real curious now. get more pics!

thanks, this is a big one

Yeah its needs a bath really bad. I found a few bees and some other bugs in there. The motor came out of my project car.
http://forums.corvetteforum.com/f-bo...ject-pics.html

I'll have a look in the morning. I didnt even think to look at it. Once the clips are off the harness you can move it out of the way with no problem.

[QUOTE=0331Marine;244185] The motor came out of my project car.
http://forums.corvetteforum.com/f-bo...ject-pics.html

I cringed a little bit when I hit the link to a vett forum. But I was plesently suprised to see a split bumper F-body. Good work going into your other ride!:D

Well, I hope I don't have to do that any time soon but it is nice to know how if and when the time comes. Thanks.

Nice hat! Are you a misplaced GA boy too?

Yeah its alot better than what they say you has to do. I've been out here for 2 years. I've got one more year then its back to GA.

I've been out here eight years! Can't wait to get back. I still have my old family place just south of Dalton. 35 acres of the prettiest woods you've ever seen and lots of national forest nearby with some nice trails to go on. The Hummer is a lot bigger than the 4x4s I had back there. Should still be okay though.

I'm from Chickamauga. I'm only 30min north of Dalton.

Good description, it will happen to us all at some point.
This also shows the reason you should ask, why GM thought of hiding the battery so you would not see that corrosion happening, why they provided a vent hose to the battery case to injest bugs, water and mud/dirt and top it off with crappy battery cable connectors.
I threw all that crap away. Well except I used the vent hose to run my winch power cables.
Some dust and dirt of course can still get in there but it is not air rammed in there. Easily cleaned out in the open and more air circulation. AGM batteries eliminate the corrosion caused by flooded acid batteries.
Attachment 16431

Great job taking pictures and writing what you did. I can't believe how dirty it is under the battery. Thanks for posting!!!

Well I have to wait another day for my alternator to get here......

Cool! I love going to Chickamauga. Love driving through the park although I haven't done it in years. My family also owns all the property down where the battle of Resaca was. We'll have to get together one of these days when we get home. I live in Bakersfield now.

Ok guys, its back together and runs great. I'm off to dinner now. I'll post the pictures and a few things you need to know about putting everything back together when I get home.

Waited all nite!

It was a late dinner.

Sorry guys. It was a late night last night and a long day today. I'll get them posted tonight.

sadly missed by family and friends,,,

Sorry guys, I was out of the country for a while. We will just leave it at that....I will finish the DIY when I get home. Again sorry about that.

Just replaced my battery last week with an Odyssey and had a dead wasp in the exact spot the dead bee was in the pic. Maybe I'll disconnect that vent tube from the front

u could stuff some wire screen in there,bug stop

I tried removing the tube, but was left with a big hole behind my grill that I wasn't real comfortable with in case of heavy rain, snow, or road debri. I have an optima so I just did away with the top of the box, disconnected the tube, zip tied it in half and tucked it out of the way.

Ok guys here we go.

New alt.
Attachment 16165

Once you get the alt in and start to put everything back together, there is one thing you need to do.

When you are putting the fuse box back together you MUST put the two wiring harnesses on the fuse box. They take some force(alot) to get them to clip in. If you try to put them in the base and then put the fuse box on, it wont snap into place.

These must snap in to the top first(where all the fuses are).
Attachment 16166

This is what it will look like if you dont put them in first. Notice the gap on the left side.
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Attachment 16167

Once they are on the box will snap into the base.
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Once you do that hook the batt back up, fuel line back together, replace the belt, and put the A/C line bracket back on and go for a drive.

Is that the same exact alt you took out and just got as replacement? Mine is a 145A stock..... :confused:

I guess I need more power than most people, so I'm picky about my alternators.

Its the same alternator. The parts store ordered the wrong one and it was going to be another week before the right one came in, so they got me one from the Hummer dealership.

Sad part about it is its time to sale the Hummer....

This was a great alternative DIY install. Especially with the in depth descriptions, pics, and commentary. Step 2 can prob. be referred to on more matters than we'd like to admit concerning some aspects of our truck.
Thanks for all the time and attention you put into this 0331Marine


Well in that case I prolly won't remove the tube. Between being to busy w/ work and some rain over here I haven't even popped the hood yet to take a look but I'm not worried about it. I'll prob. end up just stuffing an old prefilter I have in that tube. The real challenge will be first finding that filter in my garage. The insects & dirt can have free reign until then.

Alphas are 145A and are not interchangeable with the I5s.

I figured that may have been the case after thinking about it! It seemed like a really solid alternator, I beat on it for months before rebuilding it to 240A and it took it like a champ with no drop in idle voltage or output.

All said and done the fuses on all my amplifiers add up to 220A, and it had to keep up with two massive Kinetik batteries in the back, and a yellow top under the hood. Then on top of that all the rest of the factory equipment!

I expected to smoke that alternator pretty fast but it was still going strong as the day I got the truck by the time I got around to rebuilding it.

I have a company here in Ohio that is going to work on a dual alternator mount bracket, so I'll probably get another factory alt and have that run the truck, and use the second high output to feed the stereo system.

My biggest concern at this point is that I hope dual alternators won't get in the way of the Artec dual optima mount.....and I really have no way to tell unless I buy the mount so I'm little worried about taking the risk at this point. Worse comes to worse I'd rather have two yellow tops under the hood than two alts, I can always build the alternator up to 300A if needed.....

I really wish I had a way of telling but without having both parts in hand I'm kind of in a catch 22 because I'm sure no one else is running the setup that I am planning on, or at least anyone that I could get in touch with.

The bracket and alt is pretty pricey so I don't want to take the plunge unless I'm sure. Even with a friends machine shop doing the bracket for me, its still not cheap.

Thanks for the pics and the write up 0331.

id like to see 240 amps load at 15v at idle,no drop?240 load?

the stock 125 drops to 11.7 v with ext 60 amp load,,,idle,,and 2000 rpm.

now a 240 amp load,idle,no drop.

lets see pics,then ill believe

Def a good writeup! My neighbor loved my truck so much he went out and got his own, but it's an I5 and I have a feeling his alt may be getting old and tired so this could help soon! I foresee some beer bartering in exchange for help wrenching in the future.

Attached is our rides together the other night.

Well, to be fair, my amplifiers are only tuned to about half power, otherwise it wouldn't even be enjoyable to listen to. I run my system at about 25% of its potential most days, and at about 90% I start to smell my voice coils! :eek:

I'm not a fan of that smell as I'm not trying to kill my gear and have to replace it.

That being said, with my system blaring at a level that will let me get close enough to check voltages without ear plugs, with the dome lights on, and all exterior lights, I hold steady at about 13.8-14.2v except during extended bass notes (more than two to four seconds). I'm getting a stinger LCD voltage display to mount somewhere in the cockpit area so I'll try to get some pictures, or better yet video of my voltage holding steady.

I wouldn't lie to you tom, I love you too much! ;)

Now who wants to buy a 07 H3 ADV?

I would like to thank 0331marine for the post. Followed steps took about two and a half hours. Saved a bunch of money from not taking it to the shops around here. Thanks again!!

Thanks for posting!! This worked for me on my 2008 Hummer H3. Went mudding and got the alternator all jammed with mud. Luckily it failed halfway home on the highway instead of on the trails.

Some notes, and things that I did differently...

• I did not have to remove the fuel line. I was able squeak by it and get the alternator out.
• Removing the battery box and fuse box are essential!
• The belt was easy to get to if you use a 3 foot tensioner wrench from harbor freight. Best $15 you can spend to make this job easier. Removing the belt was like flipping an on/off switch.
• The fuse box is a pain in the ass if you didn't realize there are attachment levers that need to be pulled out from each side of the electrical connectors under the fuse box. I kept trying to push the fuse box in, and couldn't figure out why it wouldn't push back in. Move those levers on the grey and white connectors.

Thanks again for posting this!!

HUGE thanks to 0331Marine for jumping in first and making it so much easier for everyone else to follow :)

My 2006 H3 with 160,000 kept draining the battery. Luckily, I never got stranded. always found it dead in the driveway the next morning. No warning. Since no codes, no warning lights, no DIC messages etc I assumed it was somebody leaving the dome light or the aftermarket radio left on all night.

Last Friday the battery light came on intermittently for the first time and the word BATTERY popped up in DIC. An hour later they were on full time, 10 seconds after the truck starts. No other issues, truck ran fine, lights never dimmed, even with all four power and windows etc.

I put a volt meter on the pos/neg terminals and it read 11 and change running all accessories, no accessories or stone cold off. I don't know much but I know that's supposed to be at least 13 volts coming off of there.

Ditto rallyrcr's bullets. I had to GENTLY PRESS - not bend - A/C rigid lines back a hair. Hope I didn't accelerate any stress fractures in the aluminum, I also have to to say, looking at the entire fuse box assembly out of the truck, sitting on the workbench was a very unsettling sight :eek:

Thanks again, GREAT write up!

Followed this perfectly, thank you for saving me money.

Now, if I can figure out why it still says my alternator is overcharging, even though I just replaced it..

I wanted to thank you for posting this information online. It saved me $450.00! I always said that I didn't want a truck that I couldn't work on myself. As a new H3 owner, I am thankful for your kindness in sharing this information. Thanks again!

You don’t have to remove fuse box or disconnect fuel line. It is tight but will come out top.

Moving this to the H3 FAQ section where it will be easier to find when somebody needs it.