Horror movie where cars won't start once turned off [closed]

Its the "Demon Wind" (1990) - I've seen it as a kid and gave me nightmares for weeks:

Here are fragments of the movie(warning kids!, its a horror!!!)

In the film a group of college students (both men and women) visit a place in a desert-like area.

It was a farm-like building with a big shed. What is quite interesting, from the front you can see the whole building, but one character goes behind it and sees that it is only a front wall. There is inscription written on the wall that starts the whole mayhem.

A little girl, presumably a witch, is shown pointing a bone towards their cars from far away while standing on top of a mountain.

You can see her at the first seconds of the fragments above. She also shows up (as a last surviving monster) in the very end of the movie.

When the students reach their destination and turn their cars off, they will not restart.

Checked.

The students can't leave the place, and they use a book to cast a protection spell on the place.

There is a magical book and a few magical daggers - the book protects the house but later on protection fades. Daggers have the ability to free the soul trapped inside the monsters.

There's also a scene where the spirit of a priest or holy figure shows up. The demons convince the holy figure to "take them" and they combine into a big demon or some such.

Indeed: towards the end of the movie a priest walks from the barn addressing the monsters as his children. Then they are joined together into one huge monster that is able to break the protection spell. To counter this, the main character turns (via spell) into angelic-like figure.