Just moved and can't find the furnace filter to change it. Lenox Pulse Model: G1403-60-20 made in 1990, I think. Would appreciate the help. Thanks

Coud be anywhere, but should be somewhere in the return ,look inside the furnace where the return is attached,maybe outside the furnace in return duct, could even be behind the return grill/grills,, and you may find that someone has removed the filter and not replaced with a new one,, but is very important to find where it is or was and replace

Thanks. I'll look.