2008 expedition, my drivers side seat belt wont latch, is this something i need to carry to the dealer, or can i fix this myself ?

I had a terrible time getting a dime that fell into the latch slot out. It is easy for change & things to fall out of pockets. Belts aren't cheap, You usually need to buy all the parts for one seat position. Take a peek in there and see if you can't fish something out with a pick tool if some sort.

The button on my Nissan stuck open. They have a life time warranty on seat belts. The service adviser told me that most manufacturers do. Call your local dealer before buying anything.

dealer should fix for free. it's a safety feature.

Me too! And it was a dime! More than once in various cars!
For sure, peek down in there - some debris is likely the only problem.

I agree. I had this problem on my 04 Grand Marquis a couple of a years ago on a trip to Seattle. Went in to IHOP to eat breakfast, came out an hour later and the seat belt wouldn't latch.

So I drove without it to the next town, and in my mind I started looking for the nearest Ford dealership to buy a new belt assembly.
While I was filling the tank, my teenage daughter got a flashlight and looked inside and saw a small piece of paper. She took out a nail file and was able to fish it out. It's worked fine ever since. That was 2 years ago.