Turn Signals blink fast initially then return to normal?

I searched but found little help.

Everyone says tail light bulb housing.

I see this for removing the tail lights
https://www.youtube.com/watch?v=qoEkEhEE_kg

But, what part number do I need to replace it with?
Do I need to cut wires?
Do I need to replace the entire tail light assembly?


What part is typically bad?
The wiring harness or the tail light housing?

Turn Signals blink fast initially then return to normal?