The FSM blurb suggests that the output affected by a short or overload is protected, not actually shutting the entire CC unit down. Having gone through the ACC in the '86 (which should be the same in the '87) there's no fuse and certainly no "circuit breaker". I suspect the protection system senses the current on the base of the transistor pack and shuts it off.

In the case of the OP, I'd still be looking at the ignition switch. If the ACC were shutting down, it should do it in "crank" just like it would in "run". Since the blower runs in "crank" but not in "run", I'd suspect worn or burnt contacts in the switch. There is a dedicated high current contact in there to control the blower.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

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