OK, what is it, are they related?
 

I was involved in a discussion of the purpose of a MB part last week and related that I had seen something on a 91 MB that I had never seen before. Not only is the model 14 years old but it has been servcied in our shop for most of those years... I just noticed it/them.

I have done no research yet, so I don't know the answer. Lets see if anyone else does. I have two pictures. The only thing that links them is my not knowing what either do. I don't even know if they are part of the same system.

parts
 

steve is the car european or US market? do either have a part number? can you share the vin number?
Ray

US car, 300D 2.5T. 1991. Sorry about that. The line coming from that heater hose looks just like a brake line. I could only see the one line so it isn't an in and out that would be used for some form of heater.

vin
 

send the vin, i will do a little research and see if i can find anything, could it be an auxillary heater or a block heater? no part numbers?