I can easily swap out the ground cable from my 1980 (hot cable is obviously more difficult). The 1980 works, but I can tell you from visible inspection that the 1979 cables look practically new. This car seemed to have been something of a garage queen for the PO. The 1980 cables have some signs of green corrosion on the exposed part that goes into the terminal, and the terminal is off-color. The 1980 works, the 1979 doesn't.

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Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT