good news: 83' 240 does not have an "evil servo". not sure but some of them may have the most advanced version of the automatic climate control system that went into w123s. if you have a horizontal row of buttons then its an ACCIII. reference for your searching.

if it has the manual knobs that control everything then it known as the ACCI and it's probably pretty simple to fix.

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"