Have Mercedes Questions? Ask a Mechanic for Answers ASAP
Hello, my name is Bobby. Thank you for the question. If the doors will not open at all and it is that cold outside then the battery in the car may have failed. You will need to use the blade key to open the trunk and either charge or try jumping the battery. That should take care of it. If the key will not open the trunk then you need to try spraying some lubricant like WD40 on it to see if it will release the tumbler. Let me know if you need more help.