On the dash it says service 4 wheel drive. The previous owner said be read online that light comes on after certain mileage . He said it would say that from tkme to time when he got it with 80k. It's got 93k now. Car doesn't not show any signs of problems. Is this a major issue or a reset issue? Any help is appreciated

 

You can get a cheap OBD BT scanner and see if it set and codes. That would tell you exactly whats going on. Or at least a place to start.
Then theres apps for your smartphone that connect and you can read and reset the codes.

 

I had the same problem several years ago. And when I came to very knowledgeable mechanic so he fixed it for me for free and he told me how to fix it by myself in future if problem will come back: Try to play with your 4Hi and 4HI LOCK buttons, pressing them one after another one to let your transfer case motor to switch mode of transfer case from one to another one. You should do it when your track is not moving( you can do it even during long red light waiting on intersections!) and you should do it at least 20-30 times pressing buttons back and forth letting TC Motor to change mode for transmission. That mechanic-guy told me that it's a "Rule of 30 switches". When you do this procedure your TC motor start to work again and clean some residue this way, that could stay on the rotor and electric brushes of TC Motor after it didn't work for long period of time. So when your TC Motor do it for about 20-30 time, changing modes from 4HI to 4HI LOCK and back it could fix your problem! But be sure that your truck is STATIC and it's not moving during that procedure!
After one or two years this problem with DIC message:"Service 4WD"came back and I fixed it right away with this procedure!
I hope that it could help you for free! By the way, that mechanic guy was former GM specialist and employee!
Try it! And good luck!

 

Hey Collega would that trick work on a h3 ? Im thinking it would not that I have a problem but for future reference. BTW I didn't see any pics of your hummer on your page.

 

I think, it could work on H3 too because, in my understanding, it's the same idea and it should work the same way, like it works on H2. I never heard that somebody did it on H3, but TC Motor could work the same way on both Hummers.
I try to put some pictures to attach them to my profile, but I couldn't do it. I will try it again,

 

Haven' done any research on it for h3 but you cant go wrong for the price.it would be worth a try. also thinking maybe your pictures are too big

 

Yes, this experience is priceless and we can always could use it( better we don't need to use it, actually!). There are always smart people around, that we can learn from them good things!

 

This is true because it would be a sad day if you couldn't learn something new

 

we are here BIG ARMY of HUMMER SUPPORTERS on forum! So everybody has his own experience and in this case everybody could contribute something very useful for other Hummer and not Hummer owners, when people need it(hopefully need it just for fun, not for costly repairs!)

 

So go from one button to the next just keep hitting them? How do I know when to stop?