[particlewave]

Pictures?

First, you need to remove the bad locking bar. Next, with no locking bar in, figure out why the socket isn't seating. My guess is that the car side of the socket connector is loose or out if place as this is common. Lastly, install new lock bar and make sure that the tool you are using to turn it is a snug fit and not loose (you don't want to strip the new one).

Reinsert the headlight and be careful about turning the lock bar. When everything is aligned right, the first 1/4 turn toward the rear of the car(with tool handle starting at upright position) should move the headlight back snug...that's how you know the lock bar is in the correct position and the connector is aligned. Now, the last 1/4 turn to the rear will be harder, finishing with a loud pop which indicates that it's locked.

Primary point: remove lock bar and find your binding/seating issue.