Is it permissible to work in the installation and maintenance of refrigerators and air conditioners for non-Muslims, knowing that alcoholic beverages may be placed in the refrigerators, and is it permissible to install lighting for commercial shops that include both permissible and prohibited items?

There is no objection to repairing tools that may be used for both permissible and impermissible purposes. This is based on the Prophet's (peace be upon him) statement to Umar when he presented him with a silk garment: "Sell it or use it for your needs." However, if it is highly probable that the owner intends to use it for impermissible purposes, then repairing it is forbidden, due to Allah's (the Exalted) saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression."