The ac system also removes humidity which helps clear the window faster.
There is no A/C defrost relay. The defrost mode of the heating and air coditioning is a default mode whenever the system is not operating as it should. It automatically goes to defrost mode when the system is not operating as it should.
DO NOT FEAR THIS !!! The ac comes on with the defrost: because do you ever use your ac in the winter? me neither. Manufactures have made the ac come on with the defrost to prevent the ac compressor from seizing up. Since we never use them in winter, at least in cold climates. Cheers and drive on.
cooling fan relay short or bypassed or defrost or ac selector on
does the ac just stop or does the defrost also come on out of the blue?
does fan door motorized or on a vaccuum line when you switch from AC to defrost?
Yes, the windshield defroster will turn the A/C compressor on.
Yes, it will run when in defrost or mix.
Yes, the ac will run in the defrost position to dry the windshield.
The fan motor has failed and will need replaced.
Could you be a more articulate in your question please.
If it has AC assist and the compressor is shot, cut the belt or disconnect the defrost from the compressor.
Did you happen to move it to Defrost when you turned it off? The ac compressor also runs in the defrost cycle to keep the seals lubricated during the winter months when the ac is not used.