GMC Troubleshooting Questions? Ask a Mechanic for Answers
I am sorry your having this problem
99 % of these that will loose the shifter position and will not auto lock or unlock the doors are caused by the park neutral switch on the drivers side of the transmission not sending the correct position to the computer
when this happens the position will be blank or wrong and when the computer does not see a gear change the BCM computer never sees the position move so it will not auto lock or auto unlock the doors
the odds are replacing the park neutral switch as seen in this picture will correct this issue you are having
how are you making out ?
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