if there is it will be on the passenger side under the glove box. There is a big piece of black plastic that hangs down a bit. It is held on by 6 or 7mm screws, pull that cover off and if there are the filters you should be able to locate them.
03 did not have them-- but you can cut the bottom of the housing at the outline, insert filters and fab a cover. Not hard to do! I did it on my 04. :drink
A forum community dedicated to Chevy and GMC Duramax diesel owners and enthusiasts. Come join the discussion about modifications, towing, classifieds, troubleshooting, maintenance, and more!