SPA83 has an advantage over me in that he can scan the schematic. The LAMM schematics are still some of the best in the world and generally nothing is missing and the cross references are all clear and work. 30-30 shows a cb B1-62 "ram air temp & probe heater" via contact of R2-100 the right probe and port heat control relay via contacts of R2-5 via a current sensing transformer direct to the heater element. There is shown one further tap from the cb which is to the Thrust Rating panel power supply.
To answer the question about routine pulling of the Left Ground Control Relay to put some systems "into the air" yes routine, the only simple way. I can't remember if it was a daily item.