Car hates rego checks - flashes airbag light each year in protest

[Roadrunner]

Believe it or not but this has been happening for about 4-5 years now.
Rego is due early December.
Literally days before, or the day of pink slip booking I get 7 airbag blinks (passenger side). Unplug replug connector all good. Never comes back till same time a year later.

Thought I would beat it this year and got pink slip done 2 weeks ago at lunch time. I kid you not that afternoon on the way home from work - airbag light starts flashing! At least it happened post pink slip this year!

What the hell?
Never had it any other time of the year. Always late November early December and within days of a pink slip booking.
Even weirder, I’ve been driving it each day to work since rego check. Never blinks on the way to work in the morning. Always blinks in the arvo on the way home.

Guess I’ll just unplug and reconnect the plug and it won’t happen again till this time next year.

Any suggestions? Has to be heat related right?

[bruce]

Humidity. I bet there's some corrosion on the connectors somewhere.
I'd disconnect the battery and remove the airbag to check the back of it.

[93_Clubman]

Perhaps there's something you do in prep for the annual rego check that triggers the issue.

[bruce]

It happens roughly same time of the year which points to weather conditions. Thus similar humidity this time of year which points to some corrosion somewhere.

[Roadrunner]

That's a good suggestion Bruce. The connection pins look fine and I give them a spray of contact cleaner each time this happens. I'll trace the wires further back to the bag.
I'm in Newcastle NSW so we don't get "North QLD humid" but it does ramp up some days. Still quite cool in the morning with hot afternoons at the moment. I'd have thought this would happen all the way through till Feb if it was humidity.

Rego check prep for me is checking the blinkers and tail lights work. That's it.

[bruce]

If you decide to unplug your airbag, be careful as some connectors can be fragile (I don't know if Mazda's are).