I recently bought a 2007 Ford Focus.
This morning was the first time the car was in freezing temperatures since I have owned it and after unlocking the door and opening it the door latch would not engage and hold the door closed.
The temperatures was only zero degrees Celsius at most last night and the windscreen of the car was not frozen.
I don't believe the lock was frozen, could this be a problem with the latch spring on the door?
I'm guessing water in the latch mechanism somewhere. Try displacing the water (when it's above freezing) with some WD-40, let it sit awhile, then lubing with a silicone based lube (not sure if that's the best option, but it's what comes to mind, would like to see other opinions on the best latch lube).
It if was freezing outside, it was almost certainly colder inside the latch mechanism. It sounds like ice formed on the spring and / or the latch hinge. You were able to use the leverage of the door handle to move the latch against the friction of the ice but then the spring wasn't able to push it back.
When something like this happens, I would suggest either using a heat gun or hairdryer right on the latch or, if that's not feasible, getting in the car with the heater on full blast. At a certain point, the latch will pop loose enough to hold the door closed.
Once the latch is nice and warm, Brian is correct about WD-40 for water displacement (thus the name). The ambient temperatures don't necessarily have to be over freezing but it will help.
Once you feel that the water has moved on, I'd lube the latch liberally with standard white lithium grease. I like lithium grease because (a) it works almost everywhere, (b) it's cheap and (c) it's relatively high visibility (so I can see where it is and where it has rubbed off).
I have a Focus 2010 model and can confirm that Bobs advise is absolutely right. The same thing happened to me this evening when my passenger door when opened wouldn't latch in again (currently outside temp minus 5c). Just 10 seconds using a hair drier on the latch solved the problem for me. I also then sprayed the mechanism with WD40 for good measure. Had the same thing happen on an 05 Focus, but then it was door wouldn't open at all on drivers side, so had to slide through from passenger side, once cabin temp was raised all was ok.... I'm guessing that a Ford Focus won't be the car of choice in Russia! Thanks for advise Bob.
Myself and my wife both have Ford Focus '07. In Ireland, so same as UK model. Both of us have had this problem this winter, temp falls below zero, key fob allows door to unlock, and the handle action opens the lock, but it is too frozen to close. In her case holding it and running sitcom worked quickly. In mine I had to wait a lot longer. Seems like a known issue with Ford!
Great advice from previous posters, will wd40 our locks this weekend in case of another January freeze
