I did not use my 99 2500 for almost 2 months. It was parked under the carport out of the elements and when I used it this weekend there was a terrible odor out the heater duct. I removed the heater fan and cleaned out a mouse nest made of hood insulation and hay. I had to reach my arm way up towards the top of the dash to get the whole nest. Anybody ever have this happen and did you find how they got in the heater duct? I feel they must be getting in from the engine compartment or cowl but I can't see where. Anybody have any ideas. Thanks, Charlie.