well I found this
http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1993@@1993&makeid=63@@MERCEDES+BENZ@@X&modelid=6132%3AED%7C10000011%3ASM%7C847%3AMBC%7C1486@@190E+2%2E6&catid=242213@@Climate+Control&subcatid=242253@@A%2FC+Evap+Temp+Sensor&mode=PD

but your Klima suggestion is compelling; how to test it to find out if it's the culprit?

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