I have a Hyundai Elantra 1999 2.0L GLS, the air conditioning has no problems, but I do not find where the air filter of the air conditioning is located to change it, because I do not know if they had changed it before, and it has been on time
The air conditioning filter is not changed, what you will look for is the antipole or abitacle filter.
Remove the glove compared a little to the left a black plastic housing that goes from top to bottom tasks and pulls how white the filter is, square of about 20x25 centimeters approximately.