Last week when the temps hit the second night in a row of around 25 degrees below zero, my car radio stopped picking up AM channels. I could hear FM stations loud and clear. AM stations all disappeared. I thought they'd come back when the weather warmed a bit, but they have not.
Any ideas on what happened and how to fix it?

I'd assume a bit of condensation froze and then shorted out the AM receiver side of the rdio, but I'm just spitballing.