2022 Kenworth t680 - ticking sound with engine off

the engine is OFF, this ticking sound happens frequently. No pattern as to when, except that my engine is off. When sitting inside, it sounds like the sound is coming from somewhere in line with my steer axle.
I would love if someone knew what this is, if it can even be identified by sound alone.
It may or may not be related, but my bunk heater stopped working as well. When I try to turn it on, it will start up, but after a minute or two the screen flashes and factory resets. I say it may be related because it does the flash/reset right when one of those loud clicks happen.

 

I'm pretty sure it's igniting, initially, at least, because for that first minute that it does come on, it blows hot.

 

I do have an auto, yes. PACCAR engine, if that makes any difference. I also had someone else suggest it was transmission related, I'll look into that, thanks.

 

It doesn't smoke. It simply shuts off. I've had other trucks where the bunk heater wouldn't ignite, those DO smoke something terrible, but that's not happening. I presumed it's a wiring issue, but then I'm just a driver, not a mechanic
It's likely unrelated to the clicking issue, but the consistent timing of it has me suspicious.