To find it, you'll need to:
1. Consult your vehicle's repair manual: This is the best resource. It will have diagrams showing the location of all modules and components.
2. Use a wiring diagram: A wiring diagram specific to your vehicle's year and model will show where the brake light system's wiring connects, which can lead you to the module. You can often find these online through repair manuals or auto parts websites.
3. Search online forums: Search online forums specific to your vehicle's make and model. Other owners may have already addressed this and shared the location.
4. Check behind the rear interior trim panels: In some vehicles, the module might be located in the rear cargo area or behind the interior panels near the taillights.
5. Check under the rear bumper: In some vehicles the module may be located behind the bumper.
Important Note: Accessing and working with electrical components can be dangerous. If you're not comfortable working with car electronics, it's best to take your vehicle to a qualified mechanic.