As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DEPARTURE CHECKS, ESSENTIAL AC BUSS SELECTOR SWITCH ON ESSENTIAL AC BUSS CONTROL MODULE WAS VERY DIFFICULT TO ROTATE. TRIED SEVERAL TIMES TO LUBE AND FREE UP SWITCH WITH NO HELP. REPLACED ESSENTIAL AC BUSS CONTROL MODULE PER MM 24-27-03, ALL OPERATIONS NOW NORMAL.