I have a 2010 H3T ALPHA and have had it for almost 5 months. The functions and controls are basically identical to that of an H3.
All of the sudden my 4Lo Locked will not work for anything. The light will flash for 5-10 seconds as if it is trying to engage but then it simply goes back to whatever it was in. This concerns me quite a bit and i was wondering if anyone with more experience could help me out. Thanks!

 

I assume you have read the manual and you are in "NEUTRAL" when trying to go into 4Lo LOCK?

Sometimes you may need to shift into 4HI Lock frist then into 4Lo Lock. Make sure you are in NEUTRAL and not going over 5mph!

If you have tried both ways several time you may have a manfunctioning transfer case module. Dealer time!

 

It was in neutral and did try going into 4Hi Locked first.. .tried both ways multiple times. Even tried going in reverse a ways and then redoing it all but to no avail. Probably time to call up Hummer.

 

Something is wrong with the system then. I had a 98 chevy blazer that did the same thing, the problem was with the button on the dashboard. That was an easy fix. Good luck

 

I'm beginnin to think I was doin it in park before because I did it in neutral today and it worked like a charm...
4Hi and 4Hi Locked both work in parked though... can you just not put it into 4Lo Locked in park???

 

yep it MUST be in neutral for 4low

 

funny cause mentally, i completely knew it was supposed to be, guess i just didnt do it. anyways, thanks guys, we're good to go!

 

lol it's all good. Good luck!