Is this the same black box you take off to get to the cabin filters?

I will give this a look.

 

Mine didn't have filters and I doubt a filter is designed to be there. I would imagine a cabin filter to be elsewhere. Mine is a 98 and I don't think there is a cabin filter for it. At least the owner's manual didn't elude to one. Yours might.

your symptoms of low heat sound like either the coil or hoses going to itare pluggedor the coil isn't having air blow through it. If both hoses are hot after driving the vehicle for a while (20-30 minutes) then I would suspect the dropped coil in the underdash black box.

 

Major,your dash is COMPLETELY different...your core is accessible...a 99 and up is not