Automatic door locks worked fine when I bought the car a few weeks ago, but now they don't. The door locks are not locking or unlocking when using the key fob (remote keyless entry) OR when using any of the automatic door lock buttons in the vehicle. When the lock button is pressed on the key fob the security system is armed (hazard lights flash, red blinking light activates), but the doors don't lock. Alternatively, when the unlock button is pressed on the key fob the security system is disarmed (hazard lights flash, red blinking light stops), but the doors don't unlock. I was in the middle of a compression test on the vehicle when it happened, so the battery was hooked up to a charger and multiple turnovers were performed to complete the test. Currently, the car starts, runs and drives perfectly. I have checked all fuses, none are blown. I have checked all grounds and they all appear clean and in tact. There are no check engine lights or codes picked up by my scanner. It's almost as if I activated a setting that needs to be reversed or have blown a fuse that I'm unaware of. Your help is appreciated!

 

Don't know if this is your problem, but there is a tiny lever within the ignition switch that senses the presence of the ignition key and will prevent locking of the doors when it is in position with the key in the ignition. The idea is to prevent you from using the automatic locking to lock the keys in the car. That lever may be stuck. Try a drop of WD-40 on the key, put it in and wiggle it around to see if you can free up the lever. Can't hurt, costs nothing, might help.

 

Did you clean ground G201? Its located on lower dash lip close to the OBD2 port, This Ground can get quite bad. Is part of if door lock circuit.