95 Jimmy-Service Engine Soon light

First off, I know very little about cars. I bought this Blazer about a week ago. Yesterday I was driving to work and the 'Service Engine Soon' light came on. I went on to work, but before I left going home, I checked and the oil was a little low. I went about a mile to the store, got oil and put in. So I thought everything was fine. The motor sounds fine, Blazer starts fine--no pings, everything is working okay, etc. The light is still on. Someone told me that some GMCs have an automatic sensor that will come on when it is time to get the oil changed. Could this be what this means? If so, how can I reset the light? I know that in some cars pulling the battery cable will sometimes work. Thanks for any help!

how can I reset the light? I know that in some cars pulling the battery cable will sometimes work. Thanks for any help!

Yes , generally that will work ... if not then go to a garage ( not a dealer ) someplace and ask the mechanic to reset it for you which involves him ( or her ) plugging in a tool in the electronics usually near the dash ... takes about 10 seconds .... most will not charge you to do it .. I had a tauras that did same thing ... nobody could find anything wrong wth it , even the ford dealership mechanics .... after getting rid of the car I learned that the problem was most likely a sensor in the exhaust system someplace..

The SES light is on because there is something wrong within the electroninc powertrain control system of the vehicle. A '95 does not have an oil condition sensor, or anything like that. If you have a code reader scan it and see what code you get. Also it should be noted, that '95 has two different computer systems used as that was a changeover year. It was either a OBD 1 system, or a OBD 1.5, and both systems require different modes of scanning.

Thanks for the help!