When one turns off the car with out powering down the a/c, fan, and radio does it contribute to short circuiting?

As long as the car is operating correctly, none of these actions will cause any harm. Manufacturers do not expect you to power down everything before shutting off the car.

No. That’s an old wive’s tale.

I sure hope not :)

Not to my knowledge.

My dad always taught me that if the air/radio/lights/etc. are already on when you start the car, a surge of power goes through them, and this can wear out those components. I know my dad’s word isn’t the be all end all, but he usually knows his stuff and his cars always last like 15 years. XD

It made a difference with older cars that did not have an “Accessory Off” position when starting the car. With an “Accessory Off” all the power / voltage would go to the starter. But it was not prevent a short circuit just a lower voltage to the vehicle.

The car talk guys on this matter. Apparently it doesn’t really matter these days, but used to, which might explain why my dad is in the habit.

I never shut anything off when I turn the car off, and my cars always last forever (knock on wood).

You shouldn’t have a problem with turning off the ignition as much as you could by turning it on with some things left on, especially with inductive loads. Like others have said, with newer models you likely will not have to worry about this.

There is a thing with inductive loads where they draw a massive surge in amperage before these loads level out to their normal rated amperage. This is why inductive loads usually rely on slow blow fuses instead of the quick blow ones that resistive loads use.

At one food plant where I’d worked as a maintenance electrician, we used time-on delay relays to power the coils of each motor starter, so that in this way the massive surge of the conveyor motors starting up was avoided, and the main would not trip. Of course there are other ways around this problem as well but that was their set-up there.