wont shift from auto
when knob is turned to shift into 2hi or 4hi light blinks as normal but returns to solid on auto - stuck in auto
Most likely the shift motor is stuck, sometimes if you lightly tap on the shift motor as someone turns the switch it will work temporarily. If it does work after tapping it needs replaced, if it don't work then you will have to run a circuit test from the control module to the shift motor.
Search Chevrolet TrailBlazer Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Chevrolet TrailBlazer Experts