Does anybody know where the cabin filter is located (if there is one) in an 2002 Hyundai Elantra??
cabin filters are normally located either behind the glove compartment,or under the hood near the firewall in a little black box.
While I doubt that a 2002 Elantra has a cabin air filter, it is possible that it was optional for that model year. Generally speaking, this feature was only standard equipment on more upscale cars in the 2002 model year.
But, the best source of information is sitting in your glove compartment. I would be very surprised if the Owner’s Manual did not cover this topic, both in terms of how to replace the filter and also the schedule for replacement.
Also, the Hyundai maintenance schedule (contained in either that same Owner’s Manual or in a separate, appropriately titled booklet) would list the odometer mileage/elapsed time factor for replacement of the cabin air filter–if Elantras came with that feature.
So, the answer to your question is probably sitting right in your glove compartment.