ENQUIRER EXCLUSIVE! HAPPY DAYS star ERIN MORAN haggard, nearly broke, and living in a rundown Indiana trailer park!

The 51-year-old actress – who won America’s heart as Richie Cunningham’s fresh-faced little sis Joanie on the ’70s sitcom – has hit rock bottom after being evicted from her California home, sources say.

Her last acting gig was years ago, and now she and her husband Steve Fleischmann are sharing a trailer with his elderly mother in the Berk­shire Pointe Mobile Home Park in New Salisbury, Ind., The ENQUIRER has learned exclusively.

“Life hasn’t been kind to Erin since the foreclosure of her home,” a family friend told The ENQUIRER.

“She and Steve moved in with his ailing mother at the trailer park a few weeks back. Erin is like an angel to her mother-in-law. She cooks and cleans for her, and takes care of her personal hygiene.

“But to look at Erin today you’d never know she was once one of TV’s biggest stars. Her peaches-and-cream complexion is a maze of wrinkles and crow’s feet. She’s aged terribly.”

Despite that, Erin – who married Steve, 45, a former furniture mover, in 1993 – is struggling to maintain a good attitude, said the source.

“She’s been mingling with the locals and tak­ing pictures with people who recognize her. She’s even frequented the local bar,” the source added.

On one rowdy night, Erin bared her breasts for the bar crowd, said the source. But in a sad twist, virtually no one knew who she was!

“Erin and Steve were having fun with some friends when someone dared Erin to flash her boobs,” said the source.

“After some heavy coaxing, Erin quickly lifted her T-shirt. But other than her few friends, no one recog­nized her! Most of the customers were scratching their heads and ask­ing, ‘What was that all about?’ and ‘Who the heck is Erin Moran?’ ”

Erin starred on ABC’s “Happy Days” during its 1974 to 1984 run, and also on her short-lived spinoff “Joanie Loves Chachi.” But her career flat-lined as she tried to transition to adult roles, and she landed just a handful of guest slots.

She competed on VH1’s “Celebrity Fit Club: Boot Camp” in 2008, but as The ENQUIRER reported, she only signed on to pocket the $75,000 appearance fee in a failing bid to save her Palmdale, Calif., home from foreclosure.

According to legal documents, she was in arrears to the tune of $315,000, and the bank foreclosed.

“It’s been a rough few years for Erin and Steve,” said the source. “He’s  trying to make ends meet by working at Walmart, and all Erin can do is try and get back to work. But with her fading looks, that doesn’t seem hopeful. For now, personal appearances are her bread and butter.”

When approached recently by a reporter, Erin snapped: “How did you ever find me? I’m sorry, but I no longer talk to reporters.”

Even though “Happy Days” was a huge hit, the gravy train has long since dried up for a bit player like Erin, according to a TV industry insider.  “Actors on older shows see little or nothing in residual pay­ments these days,” the insider told The ENQUIRER. “If Erin got anything at all, it would be chump change, certainly not enough to pay rent or mortgage.”

But Erin and the other Happy Days may have finally caught a break as a judge ruled just last week that the stars may be entitled to a slice of the licensing pie – TV residuals and the licensing of their likeness on lunchboxes, posters and games that were released when they show first aired.