My headlights stop flashing when I use the remote to lock my vehicle.

Possibility could be a problem with the central electronic module or the light switch module

There is something that is not fully closed like the hood, doors, or trunk? You could also have a bad microswitch telling the module something is still open? You would need to take it into a shop with a scanner that can read the rear electronic module parameters to see the status of all the doors. If everything is closed but say for example the hood is still open, it will not give you a lock confirmation flash because not all doors are closed. Once you closed that "open" door hood or trunk, then it will give you the confirmation flash that everything is closed and locked up. If everything is closed and parameters indicate for example that the hood wsa still open, then you would need to replace the hood latch with the microswitch. Only one of the 2 has it. But like I mentioned, this is just as an example and I have seen those go bad. So to start, open all doors, hood, and trunk and then close them all and recheck. Hope this makes sense and if it does not, let us now what we can help you with. Keep us posted please.

The rear electronic module is not seen either one of the doors, the hood, or trunk as closed. So open all door and hopod and trunk and shut them again to see what happens. If you still have no light confirmation you will need to take it in to a shop that has a scanner that can read out all door status parameters. The one indicating it is still open will be the faulty component. What I have seen is the microswitch go bad on the hood lock. Only one of the hood locks has the microswitch. So if you replace the hood lock, ask for the one with the microswitch in it. But I would start by looking at those parameters to make sure it is not something else indicating open like the trunk? These feature with the light confirmation is done so that the vehicle lets you know you have something still open when you set the alarm. Once the alarm is set and lock and walk over and close say the drivers door was open. Once it is shut the lights flash and all is good to walk away. Let us know what you find and keep us posted to the fix please. If you need more assistance then let us know.