Main power for the ACC should be coming from Fuse #5. This controls the ACC, the KLIMA relay, and the little aspirator blower behind the glovebox.

Turn the key to "run" and wait for the seatbelt buzzer to quit and listen for the aspirator blower behind the passenger-side dash vent. If the fuse is good and it is running, the ACC itself may be bad or you may have a loose plug on the back side of it.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]