After removing the glove box liner in my '86 300SL to check and see if a mouse did any damage, I noticed a hose under the dash that has deteriorated due to age. It's a made of three separate pieces. The two ends are a rubber hose about 5/8" IAD and make a couple bends. One end attaches somewhere to the firewall and the other end to (I believe) the center dash vents. The center section that connects the two ends is (was) made from a foam-type filter that's about 1-1/8"OAD & 3/8"IAD. It has disintegrated into a greasy mess. My questions are; 1: What does it do? and 2: Can I replace damaged section with a piece of vinyl or rubber tubing?

 

Yes Vinyl tubing works great, you'll only need about 2-3". Thats a connection to the temperature sensor for the automatic climate control. It just draws a slight amount of air across the sensor. You might want to use a vacuum cleaner to make sure the lines are clear, since the foam disintegrated, pieces will have been sucked into the line towards the fan. I found this problem when the car wouldn't keep a comfortable climate (switched from heat to a/c withour warning)

 

Thats good to hear on the repair. I don't believe anything fell into the tubing as it was just hanging there when I first noticed it. Pretty much fell apart when I touched it. I'll clean them out anyway. Thanks.