water collecting under crisper drawers

We have a Kenmore refrigerator bought in the mid-1980’s with no ice maker. We have water collecting in the bottom of the liner under the crisper drawers. I think probably there is something wrong with the drain but I don’t really know what to start looking at. I have a Do-It-Yourself repair manual for Kenmore refrigerators but it seems to focus on everything but how to fix this problem. We’re just not sure how to get to all the drain openings and can’t find any diagrams that show where they all are or if you have to remove parts of the refrigerator to get to them. Any help would be greatly appreciated.
Thank you,
Katt