2014 Lacrosse - Rain affects door unlocking and vehicle (not engine) starting

[kunzorama]

I've got a 2014 Lacrosse. After or during a heavy rainfall, neither my key fob or the buttons on the door handles will unlock my car. I need to use the pop-out key on the fob to unlock the driver's door. I usually then get horn action when I try to do anything, as the car thinks I'm a thief trying to break into a locked car. This has happened about 10 times over the last year or so.

Here's another clue. For the first time last week, during a heavy rain storm, I couldn't get the vehicle to start. I could get the engine to start, using the remote start function on the key fob or the MyBuick app on my phone, but when I was sitting in the driver's seat, with my foot firmly on the brake and the engine running, I couldn't get the start/stop button to "wake up" the car, so the dashboard would come to life and allow me to get the car out of Park. I tried for about 20 minutes, and shortly after the rain subsided, I was able to get the start/stop button to wake up the vehicle, so I could drive it to the dealership.

My car's at the dealership right now, but the skies are sunny and they haven't been able to get the car to act up, despite several trips through the car wash. Any idea which wires are affected and where the leak is likely coming from? I suspect the driver's side door, but it could also be up near the moon roof or near the firewall under the hood, I suppose. I'd like to help them get the car to misbehave so they have a shot at coming up with a permanent fix to this problem.

The only good news is that I just bought a 2019 Lacrosse, so I don't need the car back in a hurry. It has 216,000 miles and I want to fix it before selling it to a friend.

 

[MelsRegal]

it sounds like a corroded electrical connection that is susceptible to high humidity.
Did the dealer check both the ECM and BCM connectors?
Did the dealer carefully look at the engine compartment fuse box connections?

 

[kunzorama]

it sounds like a corroded electrical connection that is susceptible to high humidity.
Did the dealer check both the ECM and BCM connectors?
Did the dealer carefully look at the engine compartment fuse box connections?

Those sound like great ideas to me. I appreciate the suggestions and I'll pass them along to the service advisor and see he knows or can get the mechanic to follow up on them.