I can’t believe (oh wait, yes I can) that the guys did not suggest the following method of avoiding frozen door locks and latches after washing that has been working for me for decades up here in Vermont, where it gets a WHOLE lot colder than it does in Beantown. It’s really soooooo easy, and it works. First of all, it helps if you’ve maintained all your lock cylinders over the years by lubing them with a graphite lube like Lock-Ease. But even if you haven’t, simply get some WD-40 or an equivalent product and wipe down all the seals on the doors and the trunk. Shoot some into all the lock cylinders with the straw BEFORE going to the cars wash. Do the latches, too and, if there are any access holes in the door, shoot some around inside to try get some on the internal linkages. Remember, this stuff absolutely will NOT harm any electrical stuff like window motors, switches and wiring inside the door. Then, rub-a-dub-dub, make your winter filth encrusted ride all nice and shiny again, and after it’s out of the wash, repeat the procedure with the water displacement product of your choice. I have done this on days when the temperature was in the low teens or colder with no ill effects 99% of the time. In the rare instance when a lock might stick, just driving around long enough until a little cabin heat transferred through the door solved the problem. Hell, in winter, I PREFER to wash my car during a stretch of clear weather that stays well below freezing. That way I it doesn’t start to get filthy all over again as soon as I get back out on the street from the runoff of melting snowbanks. Remember, a clean car is a happy car. Not only does it look all purty, but it’s a safety deal too. You can see better through clean windows and at night with clean headlights, and all the other bozos out there can see your brake lights and directional signals a whole lot better if they’re not obscured by a thick layer of gray/brown crust!