If the lights were forgotten to be switched on before shabbos for a shabbos sheva brachos or the air conditioner was forgotten to be switched on can the goy be asked to switch them on?
Regarding the air conditioning, there is an opinion that if it is hot and the people will be very uncomfortable, that it is permitted to ask the gentile to turn the a/c on. The reason for this is based on a the halacha that it is permitted to ask a gentile to turn the heating on, on Shabbos since most people are considered a choleh, with regard to being cold. Therefore it is like asking a gentile to do melacha for a choleh, which is permitted. There are poskim of the opinion that when it is very hot, we can also apply this rule to heat, therefore if it is very hot, and people are very uncomfortable, a gentile may be asked to turn on the a/c, as it is considered shevus d’shevus b’makom tzar.
Regarding turning on the lights, it would depend on the type of lighting. If the lights are only led lights, which are only d’rabonon to turn on according to numerous poskim, then if it is very needed for the meal it is permitted to ask him to turn them on, however if the type of lighting involves a melacha, (incandescent bulbs which get red hot) then the gentile should not be asked. is d’orayso to turn them on. On the other hand, if the gentile needs the lights on, to set up the tables, and he turns them on for himself, then it is permitted, because he did it for himself)
Minchas Yitzchok 3-23, Chelkas Yackov 3-139, Be’er Moshe 6 (Kuntris Electric) 72, Mishne Halachos 5-42, Shmiras Shabbos Khilchoso 3-39. O:CH 307-5, M:B 277-27.