I've heard that its dangerous to have the AC on while the engine is off.I wanted to make sure, i was going to ask my professor but im on vacations. thank you for your help.
Only the Blower motor works with the car off, The AC Compressor WILL NOT work with the Engine off. It's not dangerous, it just won't work.
It isn't dangerous, but it is ineffective. With the engine off, the compressor that circulates the refrigerant is not turning, so what little cool that was contained in the evaporator when the engine was turned off will dissipate very quickly.
The A/C compressor itself is powered by a belt on a loop with the engine. The blower will work, but the A/C will not be cold. When the engine is running, the belt and pulle are moving, and thus the compressor is on, and youre getting cold A/C. It's not dangerous to run it with the engine off, just pointless.
AC won't run without the engine running.
