Overdrive light comes on and wont go off till you turn off motor

First check that your fluid level is full thats running in park, second when you check the fluid see if its bright red or brownish in color if it's brown does it smell kinda like onions? if yes then replace all the transmisson fluid and filter, should be done every 30,000 miles if you change fluid and filter also add lucas transmisson condtioner, and tranny will take 12 quarts but if you have never done it take itto a tranny shop, they will charge about $150.00 more or less.

I had that same problem a few months ago. I didn't really think anything of it because my car still drove the same and I didn't know it could turn into a big problem. A year ago I had my transmission rebuilt on my cherokee then this year a few weeks after that little light started having problems, my car just stopped moving. I had it towed back to the shop and they needed to replace a bad part on my transmission again. So if you've previously had problems with your transmission I would suggest getting that checked out so you don't get stuck on the side of the road for 4 hours like I did. Sorry if this doesn't help, I'm not exactly a car expert I just have lots of problems with mine.