The brake light on a 2017 Forester is usually easy to swap, but the approach depends on which light needs replacing. Outer taillight bulbs are typically user-serviceable, while the center high‑mount brake light (CHMSL) is often an LED unit that may require replacing the entire assembly. This article walks you through both scenarios and offers safety tips to keep you and your car protected.
Bulb-based brake lights (outer taillights)
Tools and safety
What you’ll typically need: replacement bulb compatible with your outer taillight, gloves or a cloth to handle the bulb (avoid touching the glass with bare skin), a small flathead or Phillips screwdriver if screws are present, and a trim removal tool if needed to lift the trunk liner. Safety: make sure the ignition is off, the key is removed, and the vehicle is cool before you start. Do not work with the battery connected if you’re near wiring.
- Open the trunk and peel back or remove the side trunk liner near the taillight to expose the back of the assembly.
- Remove the taillight mounting screws or bolts (usually two) that secure the housing to the body.
- Gently pull the taillight assembly away from the vehicle to access the bulb socket and wiring. Disconnect the electrical connector if needed.
- Twist the bulb socket counterclockwise to unlock it, then pull the old bulb straight out of the socket.
- Install the new bulb into the socket, taking care not to touch the glass with your fingers. Reinsert the socket into the housing and twist to lock.
- Reposition the taillight assembly, reconnect the wiring, and reinstall the mounting screws. Reinstall the trunk liner or trim.
After completion, re-test the brake lights by pressing the brake pedal with the ignition off, then with the engine running to ensure proper operation in all modes (brake and tail). If a bulb doesn’t illuminate, recheck the socket orientation and seals, and confirm you have the correct bulb type for your model year and trim.
Center high-mount brake light (CHMSL) – LED or unit replacement
Tools and safety
For the CHMSL, you’ll typically need a trim removal tool, a small screwdriver, and, if the unit is LED, a replacement CHMSL assembly. Some Forester trims use an LED CHMSL that isn’t user‑serviceable by replacing a single bulb. Safety: ensure the hatch is supported, the area is clear, and you’re not bending or snapping the upper hatch seal.
- Open the hatch and locate the CHMSL mounting area at the top center of the rear hatch.
- Remove any interior hatch trim or caps to access the mounting screws or fasteners. A trim tool can help lift panels without damage.
- Disconnect the electrical connector from the CHMSL module.
- If the CHMSL is an LED unit (common on many 2017 Forester trims), replace the entire brake-light assembly by unbolting or unclipping the unit, then installing the new CHMSL and reconnecting the harness.
- If your CHMSL is a replaceable bulb type (less common for the center light), remove the old module or bulb according to the manufacturer’s instructions and install the new one.
- Reassemble the hatch trim, reinstall any screws or fasteners, and test the CHMSL by pressing the brake pedal with the hatch closed.
LED center brake lights are often not designed for easy bulb replacement. If you’re unsure whether your 2017 Forester CHMSL is LED or bulb-based, consult the owner’s manual or a Subaru dealer to confirm whether you should replace the entire unit. After replacement, check for proper sealing and moisture ingress to avoid future issues.
What to do if you’re unsure which light to replace
If you’re uncertain whether your vehicle uses a replaceable bulb or an LED module for the CHMSL, or if the light doesn’t respond after a replacement, consult the owner’s manual or contact a Subaru-certified technician. A dealer or qualified mechanic can confirm the bulb type or provide the correct CHMSL assembly and installation steps.
Summary
Replacing the brake light on a 2017 Subaru Forester is usually straightforward. Outer taillight bulbs are typically replaceable by the owner, following a simple process to access the bulb, swap it, and reseal the housing. The center high‑mount brake light is often an LED module that may require replacing the entire unit rather than a single bulb. With the right tools and careful handling, you can restore full braking visibility and keep your Forester compliant and safe on the road.