Your problem most likely was caused by driving on the wrong side of the road for too long, this confused the Hummer. It is easy to fix, start driving on the right side of the road from now on, pretty soon the Hummer should be back to normal, or you won't have a Hummer left to adjust the light for anyway. If driving on the right side is not possible, another alternative solution is to start speaking to your Hummer with normal American English, it is important that whoever and whenever talking in the Hummer, everyone has to do the same, speak American. Not hard at all.
