last september, during a camping trip, our ridgelines interior heat was 0.0 , we almost froze for three days - rain on north vancouver island. we had to use a/c to clear the windows. last time it rained like this, noah built himself an ark! tried everything, almost, to find fault - fuses, fusible links etc., drove us nuts ! went to campbell river to honda dealer. interrupted everything and found the cause in five minutes. want to guess before you peek? heater valve cable slipped off air mix control linkage behind the consol above accelerator pedal. get a copy of page 21 - 64 ridgeline service manual and place it in you're owner's manual, just in case. bumpy logging roads may have shaken it off.