1993 Jeep Cherokee

Go purchase an inexpensive OBDII code reader. You can get cheap ones for under a $100 dollars at most autoparts stores (or online). It's worth the investment, specially since it will work on most vehicles made from 1996 to 2006.

Or, Autozone will either check it for you for free / or you put down a $$ deposit and use their tester - run outside check the codes - then take it back in and get your deposit/money back.

Once you get the code, post it and we'll try to help more.

Hope this helps