One problem related to transmission gear indicator has been reported for the 2005 Chevrolet Trailblazer. The most recently reported issues are listed below.
Door locks repeatedly locked and unlocked, then cascading failures, anti-lock light, engine light, other warning lights. Engine started to run rough and would not make power, engine quit. Note transmission gear indicator read incorrectly. Disconnected battery, and reconnected, engine started got me home. Three occurrences that the engine just quits. It will restart after a few minutes. Mechanic could not find anything wrong. Had another occurrence, mechanic found a code indicating the ecm may be bad. He tells me this should have noting to do with the door locks. The door locks latch and unlatch, uncommanded. Engine stops when under power. Mechanic has no course of action at this time.