Where can I find a schematic for 93 Toyota Camry

Best place to find this schematic would be Alldata or a factory service manual. There are several sensors related to the airbag system, but I am assuming you are referring to the impact sensor, of which there are usually two, mounted in the front bumper. These take about half an hour to replace on most vehicles, however, you need to be cautious of what you are doing. Be very careful when working with airbags as improper service procedures can set them off and cause injury.