I remember being scared by this movie as a child in the early 80's. I think it was some type of horror film and was about satanism or the occult. There are 2 scenes from this movie I remember:
1) A family is having a picnic near the edge of a cliff. One or both the parents get it into an old car and the handbrake is released and the car goes over the edge and they die.
2) A mother tucking her son into bed and is explaining how good the devil is and the family is looking forward to going to hell and being with the devil.
Thanks in advance!
I'm reasonably sure the film you're looking for is Jack Gold's disturbing The Medusa Touch
with Richard Burton as a psychic killer.
There is a scene in this film where a child wills an old car to go over a cliff, killing both his parents (they are not in the car but get knocked over the cliff by it) and later in life, while very sick, he is tucked up in bed by his nanny who haunts him with tales of the devil, fires in hell, etc etc.