Be careful, they changed the climate control in 90 as far as the aux fan control goes. These are all in the "right" connector. The "left" connector is the same across the W124 range.

Pre 90, the CCU gets a binary signal from the head sensor that shuts down AC at excess temperature. Another switch in that same sensor goes to the aux fan relays.

90 and after, the CCU gets an analog signal from a thermistor sensor in the head. It does the overheat decision and also triggers the fan relay.

The wiring diagram you need can be found at w124-zone.com, you'll have to register but it's free.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech