I own a 2005 Titan with 102,000 miles on it and recently there is a tap,tap,tap noise eminating from underneath the dashboard which can last from 5 seconds up to 30 seconds . It seems to be connected to the ventilation system because when I either turn on or off the air conditioning system or ventilation system it goes on and then off. Anybody else with this issue and if so anything I can do without paying big dollars at the dealership for this fix.