Residents of a Bronx public housing development are sweating out a steamy July Thursday after a transformer fire crippled electricity throughout the complex — and remained in the dark 24 hours after the blaze.

The fire broke out in the basement of a high-rise in the six-building Jackson Houses around 3:35 p.m. Wednesday, frying electrical cables and shutting down power to the entire complex, according to authorities.

The blaze was brought under control just before 6 p.m., but the effects were still being felt at the Melrose complex well into Thursday.

Five of the six buildings were running on generators, but much of the sixth remained without light — and air conditioning — as NYCHA workers tried to restore service.

“I slept in the car!” said Miguel Padilla, explaining that it’s “got AC in there.”

Padilla, who turns 50 on Friday, joked that he might wind up celebrating his birthday eating a Red Cross-issued Cup Noodles on the curb with his neighbors.

The Red Cross was also passing out Oreos, crackers and bottled water to put-out residents, and the city brought in an MTA bus where residents could chill out for a few minutes in the air-conditioning on a day when the AccuWeather RealFeel hit 95 degrees.

“It’s too hot for me,” said resident Jose Colon, 73. “I can’t sleep. I sweat all over. I felt like I was going to have a heart attack.”

Colon would know: He had cardiac surgery three years ago and sleeps with a CPAP machine because his apnea sometimes causes his heart to stop during the night.

His home health aide had to help him walk down the stairs from his 12th-floor apartment when the power blinked out Wednesday.

“If I have to walk up, I’m going to have a heart attack,” said Colon.

Another building resident, Doris Gomez, said that she’d had two heat-induced asthma attacks since the power went out.

“Look how we suffer. And in this heat too? I mean, come on,” said Gomez, 63. “How long are we going to have nothing?”