My service air bag light is on in a 2005 escalade, how do i reset it?

SOURCE: I have a 04 cadillac

I believe that you will have to take the car in to a dealership or other mechanic to have them reset the code in the computer -- just reconnecting the wire will probably not resolve the issue. If you let the mechanic know what happened, he should be able to reset the error code and resolve the issue in short order -- but he may have to inspect the system first (so that he can be sure it is still working properly and that the light will not come right back on). This should not take long, or cost very much since they likely won't have to replace anything major.
It is unlikely, but possible, that unhooking the airbag wire could have caused a problem with the system that is more major than a quick inspection can fix (these systems are VERY sensitive and are vital to your safety in case of an accident) so they might tell you that you need to replace the airbag itself of some other part in the system ... these are usually expensive to replace, but could save your life in the long run ... so I recommend replacing what they tell you is not working right (though it is your choice -- just keep in mind that the designers of the car have accounted for the airbag in their safety analysis of the vehicle so you could be putting yourself at serious risk by not fixing it). Since the advent of airbags, designers have begun to account for them in their automotive designs and safety specifications ... and they have become a vital part of the vehicle's overall safety rating, so not having a working airbag in a car designed to have one is not the same as driving a car from the age before airbags were invented. Please bare this in mind while making your decision.