Behind the dashboard of the car, the heated air is carried to the various outlets into the cab by a platic flexible pipe (similar to the pipe used on a vacuum cleaner tools attachment).
very often, this pipe can become detached from the outlet vent on the dashboard and insted of coming out into the passenger copartment it is dumped into the void in the dashboard.
Put your hand up the back of the dashboard from underneath and see if you can feel the open end of the plastic pipe blowing warm air arounf behind the dashboard, if you can then it is a simple matter to relocate it back onto the pastic distribution grid on the dash.
Stephen H, November 2011
