This is described in more detail in a more recent post. The problem turned out to be an exposed 12v wire the runs from the clutch magnet to the plug pin. Because it is routed underneath the plug holder bracket, it is impossible to see without taking the bracket off.

Keep this in mind when your 200K+ a/c starts to give you a problem.

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03 CLK430 Cabrio 211K Pweter Silver/ Oyster Leather
90 300SEL 214k Pearl Black/ Alto Grey/Black Leather

Prior: 85 190E, 88 300TE, 89 300TE, 90 300E 2.6, 90 300TE, 92 300E 2.6, 91 and 93 300SL, 87 Ferrari Mondial Cabrio