I had a similar problem with a D from a junkyard. It had been there for 7 years with 7 rats nests in it. Those creaters had chewed hole to get everywhere in the car. Most of the hole you describe had nests in them and had to be be thoroughtly cleaned. The problem was one have gotten into the heater/AC box. I had to remove the complete unit from the car, clean and seal it to get rid of the odor. "Kills" is a product intended for this purpose. Bob