That could be the hose for the interior temperature sensor. One end is hooked up to a small aspirator motor that creates a slight vaccuum to pull interior air thru the sensor. These foam hoses crumble after all the years on them. A quick test you can do on the sensor is to cut a 3/4"x3/4" square piece of paper and place it up against the inlet grille of the interior temp. sensor with the climate control running. If the aspirator motor is functioning and the hose is intact, the paper should be sucked and held against the grille. If it doesn't stay, it's a good bet that the crumbled hose you found is the one for the temp sensor. Good luck!

Nolan