black hose, what is it
 

i recently took out my glove box and i saw a black hose about .25" diameter. it appears that a portion in the middle was removed, does it have anything to do with heating or air; the air is currently out of order. the hose appears to come from the firewall on the far right side and go to the middle of the dash where the vents and control unit is located, any thoughts? thanks bryan 1985 300d turbo

That is the air temperature sensor hose. In the middle of the dash is a vented square. This is the temperature sensor for the AC/Heat system. A foam tube should connect the sensor to the black tube you describe ( the foam tube is from the center of the dash to the hard tube). That black tube goes down to the evaporator case and allows the fan to such air over the temp sensor and into the fan housing.

Here is the post about the tube. The picture, scroll down for it, is the dash out fo the car and upside down.

http://www.peachparts.com/shopforum/tech-help/70866-ac-temp-sensor-foam-tube.html?highlight=temp+sensor+tube+foam+dave

Dave