You should be able to use most parts from any 126 chassis. I know that my '83 and '87 have 2 different styled climate controls. At some point, MB changed the look of the climate control panel. The climate control in my '83 would be the same one used in the 126 chassis of the same year. As the system in my '87 would be the same one in all MB models of that era. It's tough trying to talk to a junk yard about a part that is not model specific, and all they know how to look up stuff is by model. You'll for a '85 300SD and they'll say they don't have it, but the part you watn would be on any W126 car. They go, "what's a 126, we don't have those" I have run into this with my '83 TD (W123)

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member