Vinegar can help you unfreeze your car doors because of its acidity. However, be careful when applying it because it can leave a stain and stink. As a result, you should not pour vinegar directly onto the frozen area.
USE DE-ICER or WD-40 TO MELT THE ICE
Within a couple of minutes, the de-icer or WD-40 should melt the ice and allow you to open your door. If the door is still frozen, apply more de-icer or WD-40 and/or give it a little more time.
This approach requires pouring a bucket of warm water over the areas around the doorframe. Doing so should melt most of the ice almost immediately. Then push on the door with your body weight a few times to break apart any remaining ice. The door should open easily at this point.
Hand sanitizer. Yes, that's right. The germ-killer you carry to prevent the common cold may just help you get out of another common cold situation. The ethanol and isopropanol alcohol that destroy germs also lower the freezing point of water, and can melt the ice inside the lock within seconds.
Preventing car door locks from freezing
The same spray you use to clean your computer will do the trick. Glycerin and Vaseline work well because of their antifreeze properties.
If your car's rubber gaskets are dirty, the dirt and debris can prevent the car door from sealing shut. This allows moisture to seep in and freeze your door. Clean your gaskets with warm soapy water, and dry them completely (so they don't freeze while you are cleaning them).
One common reason the car door lock is stuck in the locked position is due to broken connections within the door panel or lock assembly. These include a broken link from either the handle, lock cylinder, or interior locking post/switch to the car door latch.
WD40 can help with unfreezing or unjamming a lock. Since it contains alcohol-based components, WD40 can be used to defrost items that are frozen. To defrost your lock, you will need to have a clear view of the lock mechanism. Use a small amount of the WD40 spray to coat the metal components of the lock.
Believe it or not, a small bottle of alcohol-based hand sanitizer is all you need to open a frozen lock. Hand sanitizers work because the alcohol in them melts the ice that has made the lock seize up. Simply pour it on the key and wiggle the key in and out of the lock for a moment to loosen it up.
Crack Open the Windows
It might be uncomfortable and cold for the driver and passengers, but it's just for a moment. To defrost the windshield quickly, you should open as many windows as possible. That will help replace the more humid air inside your car with the drier outside air.
A popular method of quickly defrosting your car entails putting your heater on its highest setting, keeping the air conditioning on, turning recirculation off, and cracking your window a bit.
For a quick fix: According to Road and Track, this is the fastest way to defog your windshield: First, turn the heat on its maximum setting because hot air can hold more moisture. Then, turn the AC on, which will pull the moisture from the air as it passes over the cooling coils.
The lack of sealing around the door can allow cold air to come inside, and mixed with the ambient temperature of your home's interior and its humidity, this can cause the entry door to freeze shut.
Never pour hot or warm water on your windshield to defrost it, as this can also cause the glass to crack. Pouring cold water is also a bad idea, as it can freeze on the glass and make matters worse. Once the ice has started to melt you can begin removing it with a scraper and brush.
The American Automobile Association (AAA) and the Automobile Association (AA) both recommend against using hot water on a windshield, which can crack or shatter glass due to the sudden change in temperature ( here , here ).
Make or buy a spray
Saltwater de-icer spray for the car: Pour water into a spray bottle and add a scoop or two of salt. Since salt water has a lower freezing point than fresh water, it starts to melt the ice on contact. Road salt is even more effective than table salt in this recipe.
If the key turns but doesn't lock or unlock the door then this usually means that an internal mechanism has failed. Call a professional locksmith to solve this problem.
Newer vehicles are sealed up well in an attempt to limit noise intrusion into the cabin. So breaking that seal will require a bit more of a push. Try rolling down a window and opening the doors with this window wide open. The open window will allow the interior air to escape and the door should swing open easily.
If the key won't turn in the door lock, the problem could be dirt or dust in the cylinder causing the pins to be stuck in a partially raised position. If that's the case, it may be an easy fix. You can spray dry lubricant into the keyway and then insert the key a few times to get the lubricant working.