Can anyone advise me on how to get into the air inlet in the front of my vanagon, some rodents have nested inside and when I turn on the heater it really smells. I have taken the front grill off and the air inlet grill but cannot get into the vent to clean out a nest or rodents. What is the best way to get into the air ducts? I have also taken off the glove box and the panel in front of the heater box, cannot find a way to get inside the vents to clean. Any info would be welcomed.