said by Beezel:said by Ghastlyone:A lot of people don't know this, but you should occasionally run your A/C in the winter months, maybe once a week or every couple weeks. This keeps the oil in the system cycled and prevents seals from drying out and loss of freon.
Running the defrost/defog cycle on most cars in winter use the A/C.
A lot of places people live, have no need to ever run the defroster in their vehicles. I'd be lucky to run mine once in 5 years.
But yes you're correct, the defrost runs the A/C.