Is there a way I can get my child to turn on the light on Shabbos?

May a child be asked to turn a light on or off on Shabbos?

When a need arises to have a light turned on or off on Shabbos (whether due to a mistake before Shabbos, a mishap during Shabbos, etc.), some might entertain the thought of holding a young child up next to the switch hoping that they get the hint and flip the switch to the desired setting; however, this is expressly forbidden on Shabbos. The only permissible solution is to place an exceptionally young child—one who doesn’t understand the significance that flipping the light switch has to his parents—in the general area of the light switch in the hope that they might play with it and achieve the desired result. 

Following are additional halachic guidelines relevant to children of various ages:

The mitzvah mi’d’rabanan of chinuch (rabbinical requirement for education) is that a child who has reached the age of chinuch, who understands the significance of mitzvos (approximately 5-6 years old), must be trained by their father to perform mitzvos.

The mitzvah of chinuch for a lo sa’aseh (a negative commandment) applies from an even younger age. Once a child is bar havanah (capable of understanding), i.e. they can grasp the concept of something being prohibited when so told (approximately 2-3 years old)—even if they don’t yet understand why, they must be prevented by their father from violating a lo sa’aseh (a negative commandment).

A child who understands that a specific action benefits their parents—even a very young child—may not do a melachah (an activity forbidden on Shabbos) to benefit their parents. According to some Rishonim, this is due to a mitzvah mi’d’oreisa of shevisas bno (a biblical obligation that one’s children refrain from doing forbidden activities on their parents’ behalf on Shabbos). According to the Alter Rebbe, this principle applies only mi’d’rabanan, but to any aveirah (transgression) and to any adult, not just the parents; thus, if one sees any child doing a melachah on Shabbos—or any activity that’s forbidden for an adult—on an adult’s behalf, one should stop the child from doing so. 

Issur sefiyah: It is forbidden min ha’Torah (biblically) for any adult to actively cause a child of any age, even if he lacks understanding, even a one-day-old, to do an aveirah, e.g. feed a child non-kosher food. Instructing a child to desecrate the Shabbos is included in this prohibition.  #519?

https://halacha2go.com?number=519

Practical Halacha: One minute a day. By Horav Yosef Yeshaya Braun, shlita, Mara D'asra and member of the Badatz of Crown Heights.