Exterior lights flashing and clicking noise inside the vehicle

There are a number of things that can cause this, but we need to start with the basics because they are the easiest and most common.

The first thing is to check the battery and make sure it will pass a load test. Please do not just put a meter across the terminals because this will only test the voltage and not the amperage.

A load test will tell us if the battery can carry the load that it needs too.

https://www.2carpros.com/articles/car-battery-load-test

Basically, when the battery drains it will cause relays to click due to it engaging and disengaging quickly.

The next thing to do is find where the clicking is coming from.

This is most likely a relay clicking so just touching them to feel which ones are warm and clicking and that will tell us where to start.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let's run through this info and let me know what questions you have.

Thanks