My '05 Mazda3 hatchback has had this intermittent problem, and I'm worried it will be expensive to fix/troubleshoot. Any ideas?

When I use the remote door unlock, the lights "double-flicker" instead of the normal flash, and when I open the door the car enters panic mode. Repeatedly hitting the "unlock" button prevents the horns/lights from going off while I am entering the car.

While driving in the car, the door are trying to lock themselves every few seconds... hitting unlock or lock has no effect, the intermittent locking keeps trying to lock. Sometimes it stops for a while (10 minutes) and then it continues with the intermittent locking.

Recently, the lights don't flash at all when I hit lock or unlock (although the car locks/unlocks with the button press), and while I watch my car through the window of our office, the lights are randomly flashing from time to time through the day.

This happened in spring when the weather was cool and rainy, then stopped a day later when the weather turned hot and dry. It happened again for 2 days in summer during a particularly severe rain storm. It happened now with light snow/rain and is ongoing on its 2nd day.
I'm thinking moisture is entered a control module... anyone know enough about this to give some advice?
I just had a hot water heater die on me ($1000 replace), a wedding in 2 weeks (several thousand $), and I'm tight on cash and worried that once I take it to a shop they'll "get" me for several hundred more bucks.

 

Does your car have an aftermarket alarm or remote start system installed?
They are known to cause some weird intermittent problems such as you describe.

The normal control module for the power locks/windows/cruise control, etc is through the main ECU/PCM of the vehicle. I'm thinking its not that, especially since that is mounted inside the cabin and they rarely go bad unless messed with.

 

Thanks for the reponse!
No aftermarket alarm, remote start, or door locks; only stock components & no remote start.
And no issues with cruise, power windows or other functionality (so far!).

I've never messed with the primary control module ECU/PCM... I had hoped the locks were controlled from a separate module.

The driver's side door shell was replaced in 2007 after a steel I-beam punctured the door (long story...) causing cosmetic damage... maybe upon reassembly some wiring has since come loose?

As an aside, the intermittent locking has since stopped, but the lights still don't flash now when I use the lock and unlock buttons on the remote.

Luckily I managed to video record the thing happening before it stopped, so now I can show that I'm not crazy whenever I do end up taking it in!

 

Well, that sounds like a good place to start looking then. If the LS door was disturbed, and body shop people are not necessarily known for great mechanical skills, then its VERY possible that something is disturbed inside there. The master switch and other siring are part of that door.

 

May need to flash the PCM!