I cant get my trunk to shut on my pontiac bonnieville ssei . The latch wont grab

I have this same problem on mine sometimes. I did not replace anything. There is a manual fix. I pull outwards on the lock attachment (on the trunk itself) to line it up correctly. Then it shuts with no problems. It's an alignment problem. A cheap fix is patience and to adjust locking mechanism by giving it a little pull.

You may have to replace the latch on that they do go bad on car your year also if its power lock make sure power lock not engage in lock position or stuck

The manual pull up alignment works, the replacing the latch works but...... eventually you'll need repair on the lid. After two latches and two trips to the delaer over the years, it would not close. Upon inspection the plate holding the latch on the trunk had split and pulled loose. I had to have it welded back in place by a body shop.