Okay so I've been having some run-on issues with my 1982 240D. I found out something the other day. run-on does not happen when I lock the doors prior to shutting the car off. run-on does happen when I don't lock the doors. does this help diagnose where my issue is?

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1973 280 - Sold
1980 300SD - Sold
1982 240D - Stolen
1988 300E - Sold
1989 260E - Sold
1989 560SEL
1994 E420 - Sold
1997 E420
2005 CL500

Most likely a vacuum leak in the door lock and unlock system. Could have just as easily been in the HVAC systems, but in this case it is your doors including trunk and fuel door. Get a mityvac or similar tool and do some searches on this site to get a handle on vacuum issues and diagnosis.

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

I agree, that indicates that the leak is someplace in the door unlock circuit (yellow lines with green stripes). Time to break out the mityvac.

Pull a vacuum on the yellow green lines, beginning under the driver's floor mat to trace down the problem.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13