I just bought my hummer
realized the hummer selector is lit up in 4high lock
I figured it was supposed to be in regular 4
i put the truck in nuteral and selected regular 4wd and it attempts but makes a very faced paced clicking sound likes it’s trying to engage it doesn’t sound bad at all like something is busted and non metal sound but it doesn’t go into any gear selection same process for all gearing but the catch is when I try to put it back into 4 high lock it can’t find the gear and it gets stuck in nuteral and when it says it’s back into 4H lock it takes it a while key on and off to go back into gear to be able to move again it got stuck in my drive way for about 30 trying to make it go back into any kinda gear to be able to move again the lights are working for the switches and stays solid or flashes so I’m think my switch is fine

 

Sorry for spelling new iPhone doing autocorrect

 

Usually that's the shift encoder mounted on the back of the transfer case. Pretty much takes 10 minutes to replace. They are readily available....

 

If memory serves you have to select the high or low then go into Drive before it will change.
TH

 

Sitting still in neutral, mine goes into whichever selection is chosen. (2003 model)

 

Here are the instructions from the manual of an 07 H2... note that sometimes to move from 4High Lock to 4High FWD, you need to reverse - see page 130.

 

I think that's in case it's locked up from torque, such as pulling off a dirt road onto pavement. Steering left and right while idling also helps with that.