2004 XC70. My hood would not latch after opening, and the release handle didn't return to "rest" Temp is just under 32F/0C. I started the car, turned the heat to full-hot, fan on full, walk away. I had already pulled the release handle gently and slid my hand off it to allow it to snap back. 25 minutes later, I repeated this last action and then dropped the hood. The catches accepted the hood as locked.