I have a 2018 Subaru Outback. The current issue of Subaru’s “drive” magazine has an insert for new owners that advises that I should “Power Down.” Specifically “Protect your engine by shutting off headlights, windshield wipers, A/C and heat before turning off the engine.” Does it harm the engine to leave the climate control and lights on when I turn off the ignition?
I don’t know the Subaru specifically, but I don’t know how “powering down” would “protect your engine.” To me, this implies that you’re doing some excessive engine damage by leaving on these items.
There are some practical considerations other than your engine. In general, leaving things on puts an additional load on your electrical system when starting it up the next time; when the key is in the “run” position, the wipers, A/C, and fan will be on until you turn it to the start position. I don’t believe this to be enough to cause a problem unless the battery is at the end of its life.
A couple of times, I’ve left my wipers on in winter. The blades were frozen to the windshield and when I started the next day, the wipers tried to operate, the post stripped the spindle, and I ended up having to replace the blade.
I don’t see how you could leave lights on without the warning chime bugging the snot out of you.
In summary, it’s a good to turn everything off, but not worth worrying over if you don’t.