When the temperature drops to 30 and below, my car doors will not unlock and I am able to open the door while it is locked. Once, I get inside the car, I can not close the door because it will not shut. I have to drive to my destination holding the door closed or ride public transportation and wait for the temperatures to rise to close the door again. It is really a headache, every winter, it never fails. Once, I had to climb through my trunk to get into the car, because De-Icer did not work for the locks.