Need some help. 2005 LT LLY. Service 4wd on DIC. Switch (not auto 4wd) functions normal, only get message when attempting to engage 4wd. Neither hi or low range work. Switch flashes, nothing happens, get service 4wd message. Cleaned grounds, checked fuse-good, axle actuator, didn't extend, had new spare, replaced, no change didn't extend. Disconnected batteries for 5 min to clear module, no luck. Is there anything else to check/try outside of t-case motor? Thanks in advance!