My doors just randomly stopped auto locking when I shift the car into Drive. I know it's not the locking mechanisms because I just replaced them not that long ago, and they lock/unlock fine with the fob or with the buttons. Is this a faulty driver's door master switch that would cause this? My driver's side heated seat module also randomly turns on, so I'm wondering if both issues are water related from rain over the years. When I look for replacements it seems that they basically don't exist anymore, except for used. So my first question is, is the doors not locking when shifting into Drive the drivers master switch? If so, does anyone have experience with a replacement brand? Or should I try taking it apart and cleaning the connectors with alcohol? Same thing with the heated seat buttons? Or is there something else altogether causing it that I'm missing? Thanks for any assistance and advice.

 

I'm assuming you cycled through the options on the steering wheel buttons to make sure it's still set to unlock in drive? If you have the battery disconnected for any maintenance it can go back to a default setting.

As for the mechanism that tells it it's in drive, most likely that's going to be the selector switch mounted on the driver side of the transmission. It relays a lot of information to the ECM/BCM. When mine went out, it started unlocking and relocking the doors while going down the highway.

 

.... Officially I think it's still called the neutral safety switch, although it does about six or seven other things, probably more. The heat gun is necessary to soften the glue before unplugging the harness connectors.