1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Chevrolet, GMC, Avalanche, Silverado, Sierra, Tahoe, Suburban, Yukon, 1500, 2500, 3500 HVAC filter cover retrofit. I bought HVAC filters when I got my truck. I went to install them but saw a blank area where a door for the HVAC would be. I asked around at parts stores and the dealer if there was a door available for me to cover it after I cut out the blank area. The dealer said nothing was offered for my truck. I looked online and saw the configuration was the same as the 2008 and newer trucks that did have a hvac door. The blower motor and everything else looked the same in all of the diagrams for the different year trucks, so I ordered a door from Amazon for a 2008 and up truck. I cut out the center of the blank area where the filters would go. trimmed off the excess plastic. Next I blew out the dirt and debris that had collected in the bottom of the HVAC housing. installed the filters and my new cover. It took about 20 minutes.