On this page of the Horizon Forbidden West guide, you will learn how to get the Emergency Pit Stop ornament.
First, you must use the crate to reach the hole in the fence above you.
After that, jump onto the ledge, head towards the crystal wall and blow it up using Igniter.
Go inside and jump off the ledge - on one of the walls, you will find a hook for the Pullcaster.
Use the grappling hook to create a "tunnel". Go through it and find another crystal wall. Smash it and take the battery found there.
Now return to the room you were in earlier. Insert the dead battery into the charging station.
Then, pull down a crate from the ledge using the Pullcaster. Position the crate next to the charging station.
Remove the battery from the station and drop it on top of the crate. Then, push the crate to the other side, pick up the battery and insert it into the power station.
Move the crate so that it's positioned beneath a handhold that you can use to climb.
This will allow you to reach a ledge with a door. You need a code to open them, which you can find in the file right next to you. This code is 2204 - enter it and you will get into the room with the relic.