All the cold weather has led to a host of frozen door locks. I'm happy to say that despite Iowa's renowned subtropical weather, I've never had a frozen lock on any of six Volvo 700/900 cars in many years. Here's what works:

1. Immediate Fixes
-Use spray isoproyl alcohol (the little door lock cylinder spray cans that you can find at AutoZone or KMart to shoot alcohol into the lock) to free the cylinder.
-Lube the mechanism and rods with light penetrating spray.
-Heat the key: this is tough given the plastic cover on many Volvo keys, but can work if you first spray the lock with alcohol. Use a lighter.

2. Preventive Fixes
-Do NOT use WD-40 or the like to lube your locks. I use Mobil 1 spray lube (tough to find). CRC makes some superior clear synthetic lubes as does Valvoline. I am not a fan of graphite lubes: I have had frozen locks on GM cars when I've used them.
-Lube the lock cylinders and the inside mechanism twice per year. Spray a little lube inside the lock with the spray tube and then work the key.
-Use silicone spray on the rubber stripping between the frame and doors. Water can enter the dirt on this strip and freeze, holding the door quite secure. Spray it one, then wipe off with a rag to remove both excess carrier and any dirt on the weatherstripping. This seems to prolong its life.
-Move to Florida, where locks merely rust.