You need to figure out which connector you need to pull from the cluster and independently test continuity on the wires. I would just see if that black wire is grounded. If not, ground it local to the buckle and get on with life. If its the other wire, you'll need to pull the connector and see if its electrically broken. If it is, run a new wire. If its not, and the black is grounded, and the buckle shows that when you click in the belt that it mates black and green.... Then you likely have an instrument issue.

Go watch some multimeter videos, buy a cheap one from harbor freight, and get busy. Or just go get your local shop to do it for you....

 

I think best bet for me is to have dealer look at it. Wish i had a way to figuire out but this issue is exhausting and i cant even drive the truck with that damn chime. End of road for me.

 

I can't see it being a crazy expensive fix unless you need a module. the problem can only be a buckle, wiring or module. expect 1 hour diag charge then add parts and labour for the repair.. If they can't diagnose it in one hour...you are at the wrong shop.

 

Problem fixed finally! Was a broken wire near the cluster. Dealer repair. $400. 4 hours for them to find it. Dunno how a wire brakes up in there. Oh well its fixed so....