Con Edison was struggling Tuesday to restore electricity to thousands of Brooklyn residents following thunderstorms that knocked out power in the wake of Sunday’s heat-related blackout.

And if that weren’t enough, the beleaguered utility’s online outage map went on the fritz.

Con Ed said 13,000 customers lost power as a result of the storms that began sweeping through the city late Monday afternoon.

Early Tuesday evening, the company’s Web site showed it still had more than 2,200 customers without electricity, including 1,700 in hard-hit Brooklyn, where Con Ed shut off the juice in the southeast part of the borough when equipment overheated on Sunday. The company claimed that nearly all of those 33,000 customers got their power back before the storms struck, and couldn’t say if any got walloped with back-to-back outages.

Queens and Manhattan also still had blacked-out customers Tuesday evening, with about 350 and about 120, respectively. Con Ed’s Web site said the “vast majority of customers had their power back by 7 p.m.” and that all power was expected to be restored by the end of the night.

Meanwhile, Con Ed’s interactive outage map vanished from the site Tuesday morning. It was replaced with a chart listing the number of customers blacked out in each borough and Westchester, but that also disappeared Tuesday night.

The past three days of power woes followed a blackout that struck a large swath of Manhattan’s West Side on July 13, stranding people in subways and elevators and forcing the evacuation of Madison Square Garden.

The city and state have launched investigations of the outages, and Gov. Cuomo has repeatedly threatened to revoke Con Ed’s state franchise, depending on the findings.