Child won't sleep without light on

My partner has a 3 year old daughter from a previous relationship who we have at the weekend. The problem is she will not go to sleep without the landidng light on. Even if she is asleep & we turn the light off, she still wakes up crying 2 mins later and will not go back to sleep unless the light is on or someone sleeps in her bed. We have a 10 month old son who can't sleep with the light on so it is swings and roundabouts. we have tried a nightlamps which don't seem bright enough then lamps even the light in her room with a lower voltage but they are too bright, it has to be the landing light that is on. She also has this problem at her mothers house and we can't seam to get her out of it.

Please help, How do we get her to sleep without the light on?

[Kevin Kennedy, Ph.D.]

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