When the weather gets that cold after we de-winterize in preparation for the trip to Florida, I open all cabinet doors and use a fan to blow room heat into the spaces that don't normally get heat. I have been lucky so far.
Hopefully there are no cracks and just a frozen blockage.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW