Coolant on floor

Help!! I've got coolant on my passenger side floor of my 88 S-15. I took the cover off the heater core under the dash and it appears that is where the coolant is coming from. What does that mean? How do I fix it? How much might it cost??? Any help would be greatly appreciated!

you need to replace your heatercore, its plugged up. Ummm, im not sure how to fix it on a first gen. since it seems you've already gotten to it, can you remove it? get a new one and put it in. sorry i can't be more descriptive, but I did mine on a second gen, and it was a nightmare to have not paid someone to work on it from the beginning.

Yup same problem with mine, I have a 1993 Sonoma and my heater core just went out completely and I was coming here to find out if its underneath the dash and what should I take off just the glove box.. and yeah there only like 30-40 bucks for a heatercore and you want to replace it lI already have got mine so only thing I need to do is get around to it and take part the dash so my buddy that knows what hes doing can come put it in.. Im moren likely gonna have drain all the anti-freeze or not..