I have a 98 grand marquis, I recently had the front door trim start to falls off so I decided to remove it. After removal I decided it looked a lot better with out it. I then moved on to the fender trim and finally the back door. Once I got the back door half off I noticed there is a factory hole about the size of 2 nickels half overlapped. I only had done the drivers side at this point but I think it is safe to assume the passenger side is the same. Does anyone know what these holes are for? I was thinking about welding in a patch doing a skin coat of bondo and having them repainted but I'm not sure if there is a reason they need to be there.

 

this is the hole

 

I think that it does look better with out the trim. If you don't need the hole I would cover it up...

 

The holes are to hold the rear trim on. Generally when people remove the rear trims is when their doing bodywork and painting. Its so they can patch, bondo and paint over the hole. It wont hurt anything if you cover them. If you weld over them i'd advise finding a way to weld a tight mesh patch into the back and filling it with bondo after it is secured.