From the Engineer information site: This is the view of a technical bod:
When you switch off the affected side bleed and pack, you make the duct on that side pressure-less. The bleedvalve on that engine closes and there is no hot airflow anymore. So even when there was a leak, there will not be any hot-air blowing towards any component. Of course, before the leak was detected, it might have damaged certain parts, but the system is designed to detect it before its too late / parts are damaged beyond safety-limits. The maintenance action on the ground will detect the leak and inspect /repair the parts which where hit by or damaged by the hot air.
An open or ruptured bleed duct is the only thing you have then, and you may continue your flight safely with it. Even if the light remains on, it may indicate a failed detection loop. (happens more than a real leak...)
? View topic - Questions from a pilot ref Wing Body Overheat