The Aquaillumination lights have an inbult temperature sensor. If the unit is getting too hot and running the risk of components being damaged it will switch off. Once back in normal operating temperatures it will turn back on.

The power supply for the light also has this feature. It is always best to place power supplies where they get good ventilation, never place them on top of each other.

If the light is repeatedly going in to over heat mode it is worth checking that the fan has not got a build up of dust on it and that it is free to move.