luca

I have to lower my 2004 to get it in the garage, I put a heavy case in the back and I can only assume that some sort of load leveling took place because the rear has raised up and is now completely stuck in the garage. the down/lower button does nothing. Does anyone have any idea how I can lower the vehicle? it is jammed up against the roof beam.

AKoch

I assume you tried to turn the engine on and lower the suspention to the lowest position? If this is still not enough, I see two options:
1. load up the back of the vehicle with a couple of people, or a few 'heavy cases'. The suspention will compress and before the autoleveling will catch up you will be able to get out.
2. there is a semi-documented suspention hack mode, where it is possible to lower/raise the back or front individually. I tried it a few years back and it worked, but I don't remember where did I get the instructions from. May be someone here still remembers. It is done via an obscure combination of button pressing in certain order to get into this special diagnostic mode. But it will allow you to drop the back to the physical low limit.

V8_Fan

Make sure when you engage the AHC switch to "L" that the doors are all closed and your foot is off the brake. I'm not even sure if it'll work when you're in "P." You could put the tranny in "N," then take your foot off the brake w/ e-brake off and try changing the height. I just did this yesterday when having to raise it to work under the rig.