2004 Hummer H2 V8 All Wheel Drive Automatic 130000 miles
When trying to engage into either high lock or low lock, a message appears " service 4wd" and the H2 Hummer just stays in the regular all wheel drive mode. This started happening last winter and is consistant in cold weather when in MT. When I am in Houston this rarely happens, it usually will engage in either high or low lock. Someone told me the electrical actuator needs to be replaced with a pneumatic actuator. Thoughts?